Scintillation Properties of CsPbBr3 Nanocrystals Prepared by Ligand-Assisted Reprecipitation and Dual Effect of Polyacrylate Encapsulation toward Scalable Ultrafast Radiation Detectors

Lead halide perovskite nanocrystals (LHP-NCs) embedded in polymeric hosts are gaining attention as scalable and low-cost scintillation detectors for technologically relevant applications. Despite rapid progress, little is currently known about the scintillation properties and stability of LHP-NCs prepared by the ligand assisted reprecipitation (LARP) method, which allows mass scalability at room temperature unmatched by any other type of nanostructure, and the implications of incorporating LHP-NCs into polyacrylate hosts are still largely debated. Here, we show that LARP-synthesized CsPbBr3 NCs are comparable to particles from hot-injection routes and unravel the dual effect of polyacrylate incorporation, where the partial degradation of LHP-NCs luminescence is counterbalanced by the passivation of electron-poor defects by the host acrylic groups. Experiments on NCs with tailored surface defects show that the balance between such antithetical effects of polymer embedding is determined by the surface defect density of the NCs and provide guidelines for further material optimization.

Radiation Damage by Heavy Ions in Silicon and Silicon Carbide Detectors

While silicon has been a steadfast semiconductor material for the past 50 years, it is now facing competition from other materials, especially for detector design. In that respect, due to its high resistance to radiation damage, silicon carbide is one of the most promising materials. In this work, we discuss the radiation damage studies of a new, large area, p-n junction silicon carbide device developed by the SiCILIA collaboration. We have studied the general performances of several devices, as a function of fluence, irradiated in different experimental conditions with different beams. A standard p-n junction silicon detector was also irradiated for comparison. The new detectors manifest excellent performance in terms of stability of the main parameters, linearity, defect distribution, charge collection efficiency, energy resolution, leakage current, etc. Experimental results evidence a radiation resistance of SiC devices more than two order of magnitude higher than Si devices. The new construction technology applied to silicon carbide material has made it possible to create very robust devices with excellent performance. These devices will soon be available for all those scientific projects where a high resistance to radiation damage is required.

In Situ Radiation Hardness Study of Amorphous Zn-In-Sn-O Thin-Film Transistors with Structural Plasticity and Defect Tolerance

Solution-processed metal-oxide thin-film transistors (TFTs) with different metal compositions are investigated for ex situ and in situ radiation hardness experiments against ionizing radiation exposure. The synergetic combination of structural plasticity of Zn, defect tolerance of Sn, and high electron mobility of In identifies amorphous zinc-indium-tin oxide (Zn-In-Sn-O or ZITO) as an optimal radiation-resistant channel layer of TFTs. The ZITO with an elemental blending ratio of 4:1:1 for Zn/In/Sn exhibits superior ex situ radiation resistance compared to In-Ga-Zn-O, Ga-Sn-O, Ga-In-Sn-O, and Ga-Sn-Zn-O. Based on the in situ irradiation results, where a negative threshold voltage shifts and a mobility increase as well as both off current and leakage current increase are observed, three factors are proposed for the degradation mechanisms: (i) increase of channel conductivity, (ii) interface-trapped and dielectric-trapped charge buildup, and (iii) trap-assisted tunneling in the dielectric. Finally, in situ radiation-hard oxide-based TFTs are demonstrated by employing a radiation-resistant ZITO channel, a thin dielectric (50 nm SiO₂), and a passivation layer (PCBM for ambient exposure), which exhibit excellent stability with an electron mobility of ∼10 cm²/V s and aΔV_th of <3 V under real-time (15 kGy/h) gamma-ray irradiation in an ambient atmosphere.

Radiation Resilient Two-Dimensional Electronics

Limitations in cloud-based computing have prompted a paradigm shift toward all-in-one "edge" devices capable of independent data sensing, computing, and storage. Advanced defense and space applications stand to benefit immensely from this due to their need for continual operation in areas where maintaining remote oversight is difficult. However, the extreme environments relevant to these applications necessitate rigorous testing of technologies, with a common requirement being hardness to ionizing radiation. Two-dimensional (2D) molybdenum disulfide (MoS₂) has been noted to enable the sensing, storage, and logic capabilities necessary for all-in-one edge devices. Despite this, the investigation of ionizing radiation effects in MoS₂-based devices remains incomplete. In particular, studies on gamma radiation effects in MoS₂ have been largely limited to standalone films, with few device investigations; to the best of our knowledge, no explorations have been made into gamma radiation effects on the sensing and memory capabilities of MoS₂-based devices. In this work, we have used a statistical approach to study high-dose (1 Mrad) gamma radiation effects on photosensitive and programmable memtransistors fabricated from large-area monolayer MoS₂. Memtransistors were divided into separate groups to ensure accurate extraction of device characteristics pertaining to baseline performance, sensing, and memory before and after irradiation. All-MoS₂ logic gates were also assessed to determine the gamma irradiation impact on logic implementation. Our findings show that the multiple functionalities of MoS₂ memtransistors are not severely impacted by gamma irradiation even without dedicated shielding/mitigation techniques. We believe that these results serve as a foundation for more application-oriented studies going forward.

A Novel Low-Power and Soft Error Recovery 10T SRAM Cell

In SRAM cells, as the size of transistors and the distance between transistors decrease rapidly, the critical charge of the sensitive node decreases, making SRAM cells more susceptible to soft errors. If radiation particles hit the sensitive nodes of a standard 6T SRAM cell, the data stored in the cell are flipped, resulting in a single event upset. Therefore, this paper proposes a low-power SRAM cell, called PP10T, for soft error recovery. To verify the performance of PP10T, the proposed cell is simulated by the 22 nm FDSOI process, and compared with the standard 6T cell and several 10T SRAM cells, such as Quatro-10T, PS10T, NS10T, and RHBD10T. The simulation results show that all of the sensitive nodes of PP10T can recover their data, even when S0 and S1 nodes flip at the same time. PP10T is also immune to read interference, because the change of the '0' storage node, directly accessed by the bit line during the read operation, does not affect other nodes. In addition, PP10T consumes very low-holding power due to the smaller leakage current of the circuit.

Analysis and Hardening of SEGR in Trench VDMOS with Termination Structure

Single-event gate-rupture (SEGR) in the trench vertical double-diffused power MOSFET (VDMOS) occurs at a critical bias voltage during heavy-ion experiments. Fault analysis demonstrates that the hot spot is located at the termination of the VDMOS, and the gate oxide in the termination region has been damaged. The SEGR-hardened termination with multiple implantation regions is proposed and simulated using the Sentaurus TCAD. The multiple implantation regions are introduced, leading to an increase in the distance between the gate oxide and the hole accumulation region, as well as a decrease in the resistivity of the hole conductive path. This approach is effective in reducing the electric field of the gate oxide to below the calculated critical field, and results in a lower electric field than the conventional termination.

Topological Defects Created by Gamma Rays in a Carbon Nanotube Bilayer

Graphene sheets are a highly radiation-resistant material for prospective nuclear applications and nanoscale defect engineering. However, the precise mechanism of graphene radiation hardness has remained elusive. In this paper, we study the origin and nature of defects induced by gamma radiation in a graphene rolled-up plane. In order to reduce the environmental influence on graphene and reveal the small effects of gamma rays, we have synthesized a novel graphene-based nanocomposite material containing a bilayer of highly aligned carbon nanotube assemblies that have been decorated by organometallic compounds and suspended on nanoporous Al2O3 membranes. The bilayer samples were irradiated by gamma rays from a 137Cs source with a fluence rate of the order of 105 m-2s-1. The interaction between the samples and gamma quanta results in the appearance of three characteristic photon escape peaks in the radiation spectra. We explain the mechanism of interaction between the graphene sheets and gamma radiation using a pseudo-Majorana fermion graphene model, which is a quasi-relativistic N=3-flavor graphene model with a Majorana-like mass term. This model admits the existence of giant charge carrier currents that are sufficient to neutralize the impact of ionizing radiation. Experimental evidence is provided for the prediction that the 661.7-keV gamma quanta transfer enough energy to the electron subsystem of graphene to bring about the deconfinement of the bound pseudo-Majorana modes and involve C atoms in a vortical motion of the electron density flows in the graphene plane. We explain the radiation hardness of graphene by the topological non-triviality of the pseudo-Majorana fermion configurations comprising the graphene charge carriers.

Radiation Hardness Study of Silicon Carbide Sensors under High-Temperature Proton Beam Irradiations

Silicon carbide (SiC), thanks to its material properties similar to diamond and its industrial maturity close to silicon, represents an ideal candidate for several harsh-environment sensing applications, where sensors must withstand high particle irradiation and/or high operational temperatures. In this study, to explore the radiation tolerance of SiC sensors to multiple damaging processes, both at room and high temperature, we used the Ion Microprobe Chamber installed at the Ruđer Bošković Institute (Zagreb, Croatia), which made it possible to expose small areas within the same device to different ion beams, thus evaluating and comparing effects within a single device. The sensors tested, developed jointly by STLab and SenSiC, are PIN diodes with ultrathin free-standing membranes, realized by means of a recently developed doping-selective electrochemical etching. In this work, we report on the changes of the charge transport properties, specifically in terms of the charge collection efficiency (CCE), with respect to multiple localized proton irradiations, performed at both room temperature (RT) and 500 °C.

A Study of the Radiation Tolerance and Timing Properties of 3D Diamond Detectors

We present a study on the radiation tolerance and timing properties of 3D diamond detectors fabricated by laser engineering on synthetic Chemical Vapor Deposited (CVD) plates. We evaluated the radiation hardness of the sensors using Charge Collection Efficiency (CCE) measurements after neutron fluences up to 1016 n/cm2 (1 MeV equivalent.) The radiation tolerance is significantly higher when moving from standard planar architecture to 3D architecture and increases with the increasing density of the columnar electrodes. Also, the maximum applicable bias voltage before electric breakdown increases significantly after high fluence irradiation, possibly due to the passivation of defects. The experimental analysis allowed us to predict the performance of the devices at higher fluence levels, well in the range of 1016 n/cm2. We summarize the recent results on the time resolution measurements of our test sensors after optimization of the laser fabrication process and outline future activity in developing pixel tracking systems for high luminosity particle physics experiments.

3D Simulation, Electrical Characteristics and Customized Manufacturing Method for a Hemispherical Electrode Detector

The theoretical basis of a hypothetical spherical electrode detector was investigated in our previous work. It was found that the proposed detector has very good electrical characteristics, such as greatly reduced full depletion voltage, small capacitance and ultra-fast collection time. However, due to the limitations of current technology, spherical electrode detectors cannot be made. Therefore, in order to use existing CMOS technology to realize the fabrication of the detector, a hemispherical electrode detector is proposed. In this work, 3D modeling and simulation including potential and electric field distribution and hole concentration distribution are carried out using the TCAD simulation tools. In addition, the electrical characteristics, such as I-V, C-V, induced current and charge collection efficiency (CCE) with different radiation fluences, are studied to predict the radiation hardness property of the device. Furthermore, a customized manufacturing method is proposed and simulated with the TCAD-SPROCESS simulation tool. The key is to reasonably set the aspect ratio of the deep trench in the multi-step repetitive process and optimize parameters such as the angle, energy, and dose of ion implantation to realize the connection of the heavily doped region of the near-hemispherical electrode. Finally, the electrical characteristics of the process simulation are compared with the device simulation results to verify its feasibility.

Radiation Hardness of 4H-SiC P-N Junction UV Photo-Detector

4H-SiC based p-n junction UV photo-detectors were irradiated with 600 keV He⁺ in the fluence range of 5 × 10¹¹ ÷ 5 × 10¹⁴ ion/cm² in order to investigate their radiation hardness. The effects of irradiation on the electro-optical performance were monitored in dark condition and in the UV (200 ÷ 400 nm) range, as well as in the visible region confirming the typical visible blindness of unirradiated and irradiated SiC photo-sensors. A decrease of UV optical responsivity occurred after irradiation and two fluence regimes were identified. At low fluence (<10¹³ ions/cm²), a considerable reduction of optical responsivity (of about 50%) was measured despite the absence of relevant dark current changes. The presence of irradiation induced point defects and then the reduction of photo-generated charge lifetime are responsible for a reduction of the charge collection efficiency and then of the relevant optical response reduction: point defects act as recombination centers for the photo-generated charges, which recombine during the drift/diffusion toward the electrodes. At higher irradiation fluence, the optical responsivity is strongly reduced due to the formation of complex defects. The threshold between low and high fluence is about 100 kGy, confirming the radiation hardness of SiC photo-sensors.

Comparative Study of γ- and e-Radiation-Induced Effects on FBGs Using Different Femtosecond Laser Inscription Methods

This work presents an extensive, comparative study of the gamma and electron radiation effects on the behaviour of femtosecond laser-inscribed fibre Bragg gratings (FBGs) using the point-by-point and plane-by-plane inscription methods. The FBGs were inscribed in standard telecommunication single mode silica fibre (SMF28) and exposed to a total accumulated radiation dose of 15 kGy for both gamma and electron radiation. The gratings’ spectra were measured and analysed before and after the exposure to radiation, with complementary material characterisation using Fourier transform infrared (FTIR) spectroscopy. Changes in the response of the FBGs’ temperature coefficients were analysed on exposure to the different types of radiation, and we consider which of the two inscription methods result in gratings that are more robust in such harsh environments. Moreover, we used the FTIR spectroscopy to locate which chemical bonds are responsible for the changes on temperature coefficients and which are related with the optical characteristics of the FBGs.

Proton irradiation effects on mechanochemically synthesized and flash-evaporated hybrid organic-inorganic lead halide perovskites

A hybrid organic-inorganic halide perovskite is a promising material for developing efficient solar cell devices, with potential applications in space science. In this study, we synthesized methylammonium lead iodide (MAPbI₃) perovskites via two methods: mechanochemical synthesis and flash evaporation. We irradiated these perovskites with highly energetic 10 MeV proton-beam doses of 10¹¹, 10¹², 10¹³, and 4 × 10¹³protons cm^-2and examined the proton irradiation effects on the physical properties of MAPbI₃perovskites. The physical properties of the mechanochemically synthesized MAPbI₃perovskites were not considerably affected after proton irradiation. However, the flash-evaporated MAPbI₃perovskites showed a new peak in x-ray diffraction and an increased fluorescence lifetime in time-resolved photoluminescence under high-dose conditions, indicating considerable changes in their physical properties. This difference in behavior between MAPbI₃perovskites synthesized via the abovementioned two methods may be attributed to differences in radiation hardness associated with the bonding strength of the constituents, particularly Pb-I bonds. Our study will help to understand the radiation effect of proton beams on organometallic halide perovskite materials.

High-Performance and Radiation-Hardened Solution-Processed ZrLaO Gate Dielectrics for Large-Area Applications

Radiation hardness is important for electronics operating in harsh radiation environments such as outer space and nuclear energy industries. In this work, radiation-hardened solution-processed ZrLaO thin films are demonstrated. The radiation effects on solution-processed ZrLaO thin films and InO_x/ZrLaO thin-film transistors (TFTs) were systemically investigated. The Zr_0.9La_0.1O_y thin films demonstrated excellent radiation hardness with negligible roughness, composition, electrical property, and bias-stress stability degradation after radiation exposure. The metal-oxide-semiconductor capacitors (MOSCAPs) based on Zr_0.9La_0.1O_y gate dielectrics exhibited an ultralow flat band-voltage (V_FB) sensitivity of 0.11 mV/krad and 0.19 mV/krad under low dose and high dose gamma irradiation conditions, respectively. The low dose condition had a 103 krad (SiO₂) total dose and a 0.12 rad/s low dose rate, whereas the high dose condition had a 580 krad total dose and a 278 rad/s high dose rate. Furthermore, InO_x/Zr_0.9La_0.1O_y thin-film transistors (TFTs) exhibited a large I_on/I_off of 2 × 10⁶, a small subthreshold swing (SS) of 0.11 V/dec, a small interface trap density (D_it) of 1 × 10¹² cm^-2, and a 0.16 V threshold shift (ΔV_TH) under 3600 s positive bias-stress (PBS). InO_x/Zr_0.9La_0.1O_y TFT-based resistor-loaded inverters demonstrated complete swing behavior, a static output gain of 13.3 under 4 V V_DD, and an ∼9% radiation-induced degradation. Through separate investigation of the radiation-induced degradation on the semiconductor layer and dielectric layer of TFTs, it was found that radiation exposure mainly generated oxygen vacancies (V_o) and increased electron concentration among gate oxide. Nevertheless, the radiation-induced TFT instability was mainly related to the semiconductor layer degradation, which could be possibly suppressed by back-channel passivation. The demonstrated results indicate that solution-processed ZrLaO is a high-potential candidate for large-area electronics and circuits applied in harsh radiation environments. In addition, the detailed investigation of radiation-induced degradation on solution-processed high-k dielectrics in this work provided clear inspiration for developing novel flexible rad-hard dielectrics.

Energy Retention in Thin Graphite Targets after Energetic Ion Impact

High energy ion irradiation is an important tool for nanoscale modification of materials. In the case of thin targets and 2D materials, which these energetic ions can pierce through, nanoscale modifications such as production of nanopores can open up pathways for new applications. However, materials modifications can be hindered because of subsequent energy release via electron emission. In this work, we follow energy dissipation after the impact of an energetic ion in thin graphite target using Geant4 code. Presented results show that significant amount of energy can be released from the target. Especially for thin targets and highest ion energies, almost 40% of deposited energy has been released. Therefore, retention of deposited energy can be significantly altered and this can profoundly affect ion track formation in thin targets. This finding could also have broader implications for radiation hardness of other nanomaterials such as nanowires and nanoparticles.

Analyzing Gamma-Ray Irradiation Effects on Carbon Nanotube Top-Gated Field-Effect Transistors

Carbon nanotube (CNT) field-effect transistors (FETs) and integrated circuits (ICs) have been predicted and demonstrated to be some of the most promising candidates for radiation-hardened electronics. The studies mainly focused on the radiation response of the whole transistors, and experiments or analyses to reveal the detailed radiation responses of different components of the FET were absent. Here, we use a controllable experimental method to decouple the total ionizing dose (TID) radiation effects on different individual components of top-gate CNT FETs, including the CNT channel, gate dielectric, and substrate. The substrate is found to be more vulnerable to radiation damage than the gate dielectric and CNT film in FETs. Furthermore, the CNT film not only acts as a radiation-hardened semiconducting channel but also protects the channel/substrate interface by partially shielding the substrate from radiation damage. On the basis of the experimental data, a model is built to predict the irradiation resistance limit of CNT top-gated FETs, which can withstand at least 155 kGy irradiation.

Radiation Hardness of Silicon Carbide upon High-Temperature Electron and Proton Irradiation

The radiation hardness of silicon carbide with respect to electron and proton irradiation and its dependence on the irradiation temperature are analyzed. It is shown that the main mechanism of SiC compensation is the formation of deep acceptor levels. With increasing the irradiation temperature, the probability of the formation of these centers decreases, and they are partly annealed out. As a result, the carrier removal rate in SiC becomes ~6 orders of magnitude lower in the case of irradiation at 500 °C. Once again, this proves that silicon carbide is promising as a material for high-temperature electronics devices.

Radiation Tolerance and Charge Trapping Enhancement of ALD HfO2/Al2O3 Nanolaminated Dielectrics

High-k dielectric stacks are regarded as a promising information storage media in the Charge Trapping Non-Volatile Memories, which are the most viable alternative to the standard floating gate memory technology. The implementation of high-k materials in real devices requires (among the other investigations) estimation of their radiation hardness. Here we report the effect of gamma radiation (⁶⁰Co source, doses of 10 and 10 kGy) on dielectric properties, memory windows, leakage currents and retention characteristics of nanolaminated HfO₂/Al₂O₃ stacks obtained by atomic layer deposition and its relationship with post-deposition annealing in oxygen and nitrogen ambient. The results reveal that depending on the dose, either increase or reduction of all kinds of electrically active defects (i.e., initial oxide charge, fast and slow interface states) can be observed. Radiation generates oxide charges with a different sign in O₂ and N₂ annealed stacks. The results clearly demonstrate a substantial increase in memory windows of the as-grown and oxygen treated stacks resulting from enhancement of the electron trapping. The leakage currents and the retention times of O₂ annealed stacks are not deteriorated by irradiation, hence these stacks have high radiation tolerance.

Radiation-Hard and Repairable Complementary Metal-Oxide-Semiconductor Circuits Integrating n-type Indium Oxide and p-type Carbon Nanotube Field-Effect Transistors

Special radiation-hard and ultralow-power complementary metal-oxide-semiconductor (CMOS) integrated circuits (ICs) are used in the fields of deep space, nuclear energy, and medical X-ray imaging. In this work, we first constructed radiation-hard, repairable, and sub-1 V-driven printed hybrid CMOS field-effect transistors (FETs) and ICs, which integrate printed carbon nanotube (CNT) (band gap ∼ 0.65 eV) p-type FETs and indium oxide (In₂O₃) (band gap ∼3.64 eV) n-type FETs on glass substrates using a printed PS-PMMA/[EMIM][TFSI] mixture as the gate dielectric layer. The PS-PMMA/[EMIM][TFSI] mixture gate dielectric layer not only lowered the supply voltage (V_DD) by providing ultrahigh gate efficiency but also improved the anti-irradiation ability of the hybrid CMOS FETs and ICs. Specifically, the hybrid CMOS inverters exhibited rail-to-rail output with a high voltage gain and high noise margins at a low V_DD that could be scaled down to 0.4 V. Furthermore, the hybrid CMOS FETs and ICs showed excellent radiation hardness, that is, withstanding a 3 Mrad (Si) total irradiation dose (TID) at a dose rate of 560 rad s^-1 (Si), which is an exceptional result for CMOS transistors and ICs. Furthermore, the radiation-damaged CMOS FETs could be fully recovered by removing and reprinting the PS-PMMA/[EMIM][TFSI] mixture gate dielectric layer, indicating the ability to repair irradiation damage. This work provides an in-space IC fabrication technology.

Backside-illuminated scientific CMOS detector for soft X-ray resonant scattering and ptychography

The impressive progress in the performance of synchrotron radiation sources is nowadays driven by the so-called `ultimate storage ring' projects which promise an unprecedented improvement in brightness. Progress on the detector side has not always been at the same pace, especially as far as soft X-ray 2D detectors are concerned. While the most commonly used detectors are still based on microchannel plates or CCD technology, recent developments of CMOS (complementary metal oxide semiconductor)-type detectors will play an ever more important role as 2D detectors in the soft X-ray range. This paper describes the capabilities and performance of a camera equipped with a newly commercialized backside-illuminated scientific CMOS (sCMOS-BSI) sensor, integrated in a vacuum environment, for soft X-ray experiments at synchrotron sources. The 4 Mpixel sensor reaches a frame rate of up to 48 frames s^-1 while matching the requirements for X-ray experiments in terms of high-intensity linearity (>98%), good spatial homogeneity (<1%), high charge capacity (up to 80 ke^-), and low readout noise (down to 2 e^- r.m.s.) and dark current (3 e^- per second per pixel). Performance evaluations in the soft X-ray range have been carried out at the METROLOGIE beamline of the SOLEIL synchrotron. The quantum efficiency, spatial resolution (24 line-pairs mm^-1), energy resolution (<100 eV) and radiation damage versus the X-ray dose (<600 Gy) have been measured in the energy range from 40 to 2000 eV. In order to illustrate the capabilities of this new sCMOS-BSI sensor, several experiments have been performed at the SEXTANTS and HERMES soft X-ray beamlines of the SOLEIL synchrotron: acquisition of a coherent diffraction pattern from a pinhole at 186 eV, a scattering experiment from a nanostructured Co/Cu multilayer at 767 eV and ptychographic imaging in transmission at 706 eV.

Proton Radiation Hardness of Perovskite Tandem Photovoltaics

Monolithic [Cs_0.05(MA_{0. 17}FA_{0. 83})_0.95]Pb(I_0.83Br_0.17)₃/Cu(In,Ga)Se₂ (perovskite/CIGS) tandem solar cells promise high performance and can be processed on flexible substrates, enabling cost-efficient and ultra-lightweight space photovoltaics with power-to-weight and power-to-cost ratios surpassing those of state-of-the-art III-V semiconductor-based multijunctions. However, to become a viable space technology, the full tandem stack must withstand the harsh radiation environments in space. Here, we design tailored operando and ex situ measurements to show that perovskite/CIGS cells retain over 85% of their initial efficiency even after 68 MeV proton irradiation at a dose of 2 × 10¹² p⁺/cm². We use photoluminescence microscopy to show that the local quasi-Fermi-level splitting of the perovskite top cell is unaffected. We identify that the efficiency losses arise primarily from increased recombination in the CIGS bottom cell and the nickel-oxide-based recombination contact. These results are corroborated by measurements of monolithic perovskite/silicon-heterojunction cells, which severely degrade to 1% of their initial efficiency due to radiation-induced recombination centers in silicon.

Impact of Gamma Radiation on Dynamic RDSON Characteristics in AlGaN/GaN Power HEMTs

GaN high-electron-mobility transistors (HEMTs) are promising next-generation devices in the power electronics field which can coexist with silicon semiconductors, mainly in some radiation-intensive environments, such as power space converters, where high frequencies and voltages are also needed. Its wide band gap (WBG), large breakdown electric field, and thermal stability improve actual silicon performances. However, at the moment, GaN HEMT technology suffers from some reliability issues, one of the more relevant of which is the dynamic on-state resistance (R_{ON_dyn}) regarding power switching converter applications. In this study, we focused on the drain-to-source on-resistance (R_DSON) characteristics under ⁶⁰Co gamma radiation of two different commercial power GaN HEMT structures. Different bias conditions were applied to both structures during irradiation and some static measurements, such as threshold voltage and leakage currents, were performed. Additionally, dynamic resistance was measured to obtain practical information about device trapping under radiation during switching mode, and how trapping in the device is affected by gamma radiation. The experimental results showed a high dependence on the HEMT structure and the bias condition applied during irradiation. Specifically, a free current collapse structure showed great stability until 3.7 Mrad(Si), unlike the other structure tested, which showed high degradation of the parameters measured. The changes were demonstrated to be due to trapping effects generated or enhanced by gamma radiation. These new results obtained about R_{ON_dyn} will help elucidate trap behaviors in switching transistors.

Extraordinary Radiation Hardness of Atomically Thin MoS2

We demonstrate that atomically thin layered two-dimensional (2D) semiconductors are promising candidates for space electronics owing to their inherent and extraordinary resilience to radiation damage from energetic heavy charged particles. In particular, we found that ultrathin MoS₂ nanosheets can easily withstand proton and helium irradiation with fluences as high as ∼10¹⁶ and ∼10¹⁵ ions/cm², respectively, corresponding to hundreds or thousands of years of unshielded exposure to radiation in space. While radiation effects on 2D material-based field effect transistors have been reported in the recent past, none of these studies could isolate the impact of irradiation on standalone ultrathin 2D layers. By adopting a unique experimental approach that exploits the van der Waals epitaxy of 2D materials, we were able to differentiate the effects of radiation on the 2D semiconducting channel from that of the underlying dielectric substrate, semiconductor/substrate interface, and metal/semiconductor contact interface, revealing the ultimate potential of these 2D materials. Furthermore, we used a statistical approach to evaluate the effect of radiation damage on critical device and material parameters, including threshold voltage, subthreshold slope, and carrier mobility. The statistical approach lends additional credence to the general conclusions drawn from this study, overcoming a common drawback of methods applied in this area of research. Our findings do not only offer exciting prospects for the operation of modern electronics in space, but may also benefit electronics applications in high-altitude flights, military aircraft, satellites, nuclear reactors, particle accelerators, and other high-radiation environments. Additionally, they highlight the importance of evaluating the impact of damage to the substrate and surrounding materials on electrical characteristics during future radiation studies of 2D materials.

SiCILIA-Silicon Carbide Detectors for Intense Luminosity Investigations and Applications

Silicon carbide (SiC) is a compound semiconductor, which is considered as a possible alternative to silicon for particles and photons detection. Its characteristics make it very promising for the next generation of nuclear and particle physics experiments at high beam luminosity. Silicon Carbide detectors for Intense Luminosity Investigations and Applications (SiCILIA) is a project starting as a collaboration between the Italian National Institute of Nuclear Physics (INFN) and IMM-CNR, aiming at the realization of innovative detection systems based on SiC. In this paper, we discuss the main features of silicon carbide as a material and its potential application in the field of particles and photons detectors, the project structure and the strategies used for the prototype realization, and the first results concerning prototype production and their performance.

Radiation Hardness and Self-Healing of Perovskite Solar Cells

The radiation hardness of CH₃ NH₃ PbI₃ -based solar cells is evaluated from in situ measurements during high-energy proton irradiation. These organic-inorganic perovskites exhibit radiation hardness and withstand proton doses that exceed the damage threshold of crystalline silicon by almost 3 orders of magnitude. Moreover, after termination of the proton irradiation, a self-healing process of the solar cells commences.

Thin Film on CMOS Active Pixel Sensor for Space Applications

A 664 × 664 element Active Pixel image Sensor (APS) with integrated analog signal processing, full frame synchronous shutter and random access for applications in star sensors is presented and discussed. A thick vertical diode array in Thin Film on CMOS (TFC) technology is explored to achieve radiation hardness and maximum fill factor.