High-Responsivity Photodetector Based on a Suspended Monolayer Graphene/RbAg4I5 Composite Nanostructure

Ga2O3 Solar-Blind Deep-Ultraviolet Photodetectors with a Suspended Structure for High Responsivity and High-Speed Applications

The wide-bandgap semiconductor material Ga2O3 exhibits great potential in solar-blind deep-ultraviolet (DUV) photodetection applications, including none-line-of-sight secure optical communication, fire warning, high-voltage electricity monitoring, and maritime fog dispersion navigation. However, Ga2O3 photodetectors have traditionally faced challenges in achieving both high responsivity and fast response time, limiting their practical application. Herein, the Ga2O3 solar-blind DUV photodetectors with a suspended structure have been constructed for the first time. The photodetector exhibits a high responsivity of 1.51 × 1010 A/W, a sensitive detectivity of 6.01 × 1017 Jones, a large external quantum efficiency of 7.53 × 1012 %, and a fast rise time of 180 ms under 250-nm illumination. Notably, the photodetector achieves both high responsivity and fast response time simultaneously under ultra-weak power intensity excitation of 0.01 μW/cm2. This important improvement is attributed to the reduction of interface defects, improved carrier transport, efficient carrier separation, and enhanced light absorption enabled by the suspended structure. This work provides valuable insights for designing and optimizing high-performance Ga2O3 solar-blind photodetectors.

Enhanced self-powered ion-modulated photodetector based on an asymmetric composite structure of superionic conductor RbAg4I5 and graphene

Traditional strategies for self-powered devices face limitations in performance improvement due to the trade-off relationship between different parameters. Here, a new kind of ion-modulation self-powered photodetector is first proposed and fabricated by depositing superionic conductor RbAg₄I₅ on one side of monolayer graphene. The graphene homojunction is successfully formed at the boundary of the asymmetric structure due to the formation of bound states of ions and electrons at the contact interface. This kind of homojunction avoids the trade off between response parameters of traditional self-powered devices because the dissociation of bound states under light irradiation dominates the generation of a photocurrent. The experimental results indicate that the prepared photodetector can achieve great photo response with responsivity of 20 mA/W and a response speed of 700 µs for ultraviolet and visible light when no bias is applied, which is better than most existing graphene-based self-powered devices in single or overall parameters. Further, a semi-quantitative model is systematically established according to the internal mechanism and realizes a good consistency with experimental results. The work provides a new idea and offers the foundation to develop excellent self-powered devices based on superionic materials with good properties in controllability and modulation.

Physical Operations of a Self-Powered IZTO/β-Ga2O3 Schottky Barrier Diode Photodetector

In this work, a self-powered, solar-blind photodetector, based on InZnSnO (IZTO) as a Schottky contact, was deposited on the top of Si-doped β-Ga₂O₃ by the sputtering of two-faced targets with InSnO (ITO) as an ohmic contact. A detailed numerical simulation was performed by using the measured J–V characteristics of IZTO/β-Ga₂O₃ Schottky barrier diodes (SBDs) in the dark. Good agreement between the simulation and the measurement was achieved by studying the effect of the IZTO workfunction, β-Ga₂O₃ interfacial layer (IL) electron affinity, and the concentrations of interfacial traps. The IZTO/β-Ga₂O₃ (SBDs) was tested at a wavelength of 255 nm with the photo power density of 1 mW/cm². A high photo-to-dark current ratio of 3.70×105 and a photoresponsivity of 0.64 mA/W were obtained at 0 V as self-powered operation. Finally, with increasing power density the photocurrent increased, and a 17.80 mA/W responsivity under 10 mW/cm² was obtained.