Efficiency Enhancement of GaAs Single-Junction Solar Cell by Nanotextured Window Layer

In order to improve efficiency of flexible III-V semiconductor multi-junction solar cells, it is important to enhance the current density for efficiency improvement and to attain an even efficiency of solar cells on a curved surface. In this study, the nanotextured InAlP window layer of a GaAs single-junction solar cell was employed to suppress reflectance in broad range. The nanotextured surface affects the reflectance suppression with the broad spectrum of wavelength, which causes it to increase the current density and efficiency of the GaAs single-junction solar cell and alleviate the efficiency drop at the high incident angle of the light source. Those results show the potential of the effectively suppressed reflectance of multi-junction solar cells and even performance of solar cells attached on a curved surface.

Enhancing the quasi-theoretical photocurrent density of ZnO nanorods via a lukewarm hydrothermal method

A ∼10-μm-long one-dimensional (1D) ZnO nanorod array (NRA) vertically oriented on a fluorine-doped tin oxide (FTO) coated glass substrate is successfully fabricated via a lukewarm hydrothermal method. The reflection of light from the rough surface of this ultralong ZnO NRA, resulting from the variation in the characteristic length of individual ZnO NRs in a tapered geometry, is largely suppressed. This in turn favors the ZnO NRA as a photoelectrode effectively harnessing UV-light for solar water splitting, as evidently manifested in the quasi-theoretical photocurrent density that reached ∼0.9 mA cm^-2 at 1V_Ag/AgCl. A further contribution to such an outstanding performance stems from additional photocurrent generation by the ZnO NRA upon visible light illumination. This is attributed to a variety of native defects and the surface hydroxyl groups present in the ZnO NRA, giving rise to the mid-gap states that mediate the associated electronic transitions. Moreover, those lattice imperfections further boost the carrier concentration of the ZnO NRA to facilitate the carrier transport which in turn enhances the photoelectrochemical activity.

Self-Aligned Hierarchical ZnO Nanorod/NiO Nanosheet Arrays for High Photon Extraction Efficiency of GaN-Based Photonic Emitter

Advancements in nanotechnology have facilitated the increased use of ZnO nanostructures. In particular, hierarchical and core–shell nanostructures, providing a graded refractive index change, have recently been applied to enhance the photon extraction efficiency of photonic emitters. In this study, we demonstrate self-aligned hierarchical ZnO nanorod (ZNR)/NiO nanosheet arrays on a conventional photonic emitter (C-emitter) with a wavelength of 430 nm. These hierarchical nanostructures were synthesized through a two-step hydrothermal process at low temperature, and their optical output power was approximately 17% higher than that of ZNR arrays on a C-emitter and two times higher than that of a C-emitter. These results are due to the graded index change in refractive index from the GaN layer inside the device toward the outside as well as decreases in the total internal reflection and Fresnel reflection of the photonic emitter.

Improvement of Terahertz Photoconductive Antenna using Optical Antenna Array of ZnO Nanorods

An efficient terahertz (THz) photoconductive antenna (PCA), as a major constituent for the generation or detection of THz waves, plays an essential role in bridging microwave-to-photonic gaps. Here, we propose an impressive approach comprising the use of arrayed zinc oxide nanorods (ZnO NRs) as an optical nanoantenna over an anti-reflective layer (silicon nitride) in the antenna gap to boost the photocurrent and consequently the THz signal. The numerical approach applied in investigating the optical behavior of the structure, demonstrates a significant field enhancement within the LT-GaAs layer due to the optical antenna performing simultaneously as a concentrator and an antireflector which behaves as a graded-refractive index layer. ZnO NRs have been fabricated on the PCA gap using the hydrothermal method as a simple, low cost and production compatible fabrication method compared to other complex methods used for the optical nanoantennas. Compared to the conventional PCA with a traditional antireflection coating, the measured THz power by time domain spectroscopy (TDS) is increased more than 4 times on average over the 0.1–1.2 THz range.

Formation of antireflection Zn/ZnO core-shell nano-pyramidal arrays by O2+ ion bombardment of Zn surfaces

ZnO is probably one of the most studied oxides since ZnO nanostructures are a very rich family of nanomaterials with a broad variety of technological applications. Although several chemical techniques offer the possibility to obtain such ZnO nanostructures, here we show that the controlled modification of the zinc surface by low-energy O₂⁺ bombardment leads to the formation of core-shell Zn/ZnO nano-pyramidal arrays that suppress the reflection of light decreasing the reflectivity below 6% in the wavelength range of 300-900 nm. This controlled and scalable protocol opens the door to a broad range of possibilities for the use of ion bombardment to produce surface modifications for technological applications in the field of photoelectric devices and solar cells.

Exceptionally omnidirectional broadband light harvesting scheme for multi-junction concentrator solar cells achieved via ZnO nanoneedles

GaInP/GaAs/Ge triple-junction concentrator solar cells with significant efficiency enhancement were demonstrated with antireflective ZnO nanoneedles. The novel nanostructure was attained with a Zn(NO₃)₂-based solution containing vitamin C. Under one sun AM 1.5G solar spectrum, conversion efficiency of the triple-junction device was improved by 23.7% via broadband improvement in short-circuit currents of 3 sub-cells after the coverage by the nanoneedles with a graded refractive index profile. The efficiency enhancement further went up to 45.8% at 100 suns. The performance boost through the nanoneedles also became increasingly pronounced in the conditions of high incident angles and the cloudy weather, e.g. 220.0% of efficiency enhancement was observed at the incident angle of 60°. These results were attributed to the exceptional broadband omnidirectionality of the antireflective nanoneedles.

Packaging Glass with a Hierarchically Nanostructured Surface: A Universal Method to Achieve Self-Cleaning Omnidirectional Solar Cells

Fused-silica packaging glass fabricated with a hierarchical structure by integrating small (ultrathin nanorods) and large (honeycomb nanowalls) structures was demonstrated with exceptional light-harvesting solar performance, which is attributed to the subwavelength feature of the nanorods and an efficient scattering ability of the honeycomb nanowalls. Si solar cells covered with the hierarchically structured packaging glass exhibit enhanced conversion efficiency by 5.2% at normal incidence, and the enhancement went up to 46% at the incident angle of 60°. The hierarchical structured packaging glass shows excellent self-cleaning characteristics: 98.8% of the efficiency is maintained after 6 weeks of outdoor exposure, indicating that the nanostructured surface effectively repels polluting dust/particles. The presented self-cleaning omnidirectional light-harvesting design using the hierarchical structured packaging glass is a potential universal scheme for practical solar applications.

Performance Boosting of Flexible ZnO UV Sensors with Rational Designed Absorbing Antireflection Layer and Humectant Encapsulation

Flexible ZnO thin film UV sensors with 3 orders of magnitude improvement in sensitivity and 2 orders of magnitude acceleration in speed are realized via light absorption efficiency enhancement and surface encapsulation. Devices are constructed on polyethylene substrate incorporating morphology controlled ZnO nanorod arrays (NRAs) as absorbing antireflection layers. By adjusting the morphology of ZnO NRAs, the light absorptance exceeds 99% through effectively trapping incident photons. As a result, the sensitivity of the UV sensor reaches 109 000. Moreover, a mechanism of competitive chemisorption between O2 and H2O at oxygen vacancy sites is proposed to explain the phenomenon of the speed acceleration in moist environment. A new approach of humectant encapsulation is used to make H2O participant rapid processes dominant for speed acceleration. Two orders of magnitude speed enhancement in reset time is achieved by polyethylene glycol encapsulation. After a total 3000 cycles bending test, the decay in the responsivity of UV sensor is within 20%, indicating good mechanical stability. All these results not only demonstrate a simple, effective and scalable approach to fabricate high sensitive and fast response flexible ZnO UV sensors, but also provide meaningful references for performance boosting of photoelectronic devices based on other oxide semiconductors.

Selective growth of ZnO nanorods on hydrophobic Si nanorod arrays

In this paper we describe the selective growth of ZnO nanorods (NRs) on top of hydrophobic Si NR arrays. The periodic Si NR arrays, prepared through electroless chemical etching and HF treatment, functioned as hydrophobic substrates. Droplets containing ZnO seeds could be positioned on the Si NR arrays, causing the ZnO seeds to deposit selectively upon them, with n-ZnO NR/p-Si NR array heterojunctions ultimately forming after hydrothermal growth of ZnO NRs. Because of compensation for the difference in refractive index between air and the Si substrate, the n-ZnO NR/p-Si NR arrays exhibited excellent absorption ability in the visible range. Devices based on these n-ZnO NR/p-Si NR array heterojunctions displayed not only rectifying behavior but also photovoltaic effects when illuminated with UV light. The low temperature and low cost of this fabrication process suggest that the selective growth of n-ZnO NRs on p-Si NR arrays might allow such structures to have diverse applications in optoelectronics.

Efficiency enhancement of non-selenized Cu(In,Ga)Se2 solar cells employing scalable low-cost antireflective coating

In this study, a non-selenized CuInGaSe2 (CIGS) solar device with textured zinc oxide (ZnO) antireflection coatings was studied. The ZnO nanostructure was fabricated by a low-temperature aqueous solution deposition method. With controlling the morphology of the solution-grown tapered ZnO nanorod coatings, the average reflectance of the CIGS solar device decreased from 8.6% to 2.1%, and the energy conversion efficiency increased from 9.1% to 11.1%. The performance improvement in the CuInGaSe2 thin-film solar cell was well explained due to the gradual increase of the refractive index between air and the top electrode of solar cell device by the insertion of the ZnO nanostructure. The results demonstrate a potential application of the ZnO nanostructure array for efficient solar device technology.

Toward efficient and omnidirectional n-type Si solar cells: concurrent improvement in optical and electrical characteristics by employing microscale hierarchical structures

We demonstrated that hierarchical structures combining different scales (i.e., pyramids from 1.5 to 7.5 μm in width on grooves from 40 to 50 μm in diameter) exhibit excellent broadband and omnidirectional light-trapping characteristics. These microscaled hierarchical structures could not only improve light absorption but prevent poor electrical properties typically observed from nanostructures (e.g., ultra-high-density surface defects and nonconformal deposition of following layers, causing low open-circuit voltages and fill factors). The microscaled hierarchical Si heterojunction solar cells fabricated with hydrogenated amorphous Si layers on as-cut Czochralski n-type substrates show a high short-circuit current density of 36.4 mA/cm(2), an open-circuit voltage of 607 mV, and a conversion efficiency of 15.2% due to excellent antireflection and light-scattering characteristics without sacrificing minority carrier lifetimes. Compared to cells with grooved structures, hierarchical heterojunction solar cells exhibit a daily power density enhancement (69%) much higher than the power density enhancement at normal angle of incidence (49%), demonstrating omnidirectional photovoltaic characteristics of hierarchical structures. Such a concept of hierarchical structures simultaneously improving light absorption and photocarrier collection efficiency opens avenues for developing large-area and cost-effective solar energy devices in the industry.

ZnO nanowire-based antireflective coatings with double-nanotextured surfaces

High-aspect-ratio nanotextured surfaces with different morphologies (straight, core-shell type, and core-branch type nanowires) are prepared by a hydrothermal method of ZnO nanowires, followed by means of RF sputtering for core-shell type nanowires and e-beam evaporation for branch-type nanowires. The structural analysis showed that the MgO has highly preferred orientation along the ⟨111⟩ and ⟨200⟩ direction, respectively, and the crystalline continuity between the ZnO and MgO layers were also showed. Compared with ZnO nanowires, the MgO/ZnO samples drastically suppress broad and omnidirection reflection, which ascribes to the refractive-index modulation along the lateral direction of nanowires growth as well as the vertical direction. It was also shown that morphology could have a substantial influence on the antireflection property. These results suggest that double-nanotextured surface is one of the promising structures for antireflective surfaces without fine control in nanowire morphology.

Photovoltaic electrical properties of aqueous grown ZnO antireflective nanostructure on Cu(In,Ga)Se₂ thin film solar cells

A solution-grown subwavelength antireflection coating has been investigated for enhancing the photovoltaic efficiency of thin film solar cells. The 100-nm-height ZnO nanorods coating benefited the photocurrent of Cu(In,Ga)Se2 solar cells from 31.7 to 34.5 mA/cm2 via the decrease of surface light reflectance from 14.5% to 7.0%, contributed by the gradual refractive index profile between air and AZO window layer. The further reduction of surface reflectance to 2.3% in the case of 540-nm-height nanorods, yet, lowered the photocurrent to 29.5 mA/cm2, attributed to the decrease in transmittance. The absorption effect of hydrothermal grown ZnO nanorods was explored to optimize the antireflection function in enhancing photovoltaic performances.

Bio-inspired antireflective hetero-nanojunctions with enhanced photoactivity

A bio-inspired antireflective hetero-nanojunction structure has been fabricated by the hydrothermal growth of ZnO nanorods on silicon micro-pyramids. It has been shown that this structure suppresses light reflection more effectively resulting in a high photocurrent response and good charge separation simultaneously. The strategy provides a means to enhance solar energy conversion.

Liquid crystal alignment on zinc oxide nanowire arrays for LCDs applications

The zinc oxide (ZnO) nanowire arrays on the indium tin oxide (ITO) glass substrates were fabricated by using the two-step hydrothermal method. A high transmittance ~92% of ZnO nanowire arrays on ITO substrate in the visible region was obtained. It was observed that the liquid crystal (LC) directors were aligned vertically to the (ZnO) nanowire arrays. The properties of ZnO nanowire arrays as vertical liquid crystal (LC) alignment layers and their applications for hybrid-aligned nematic LC modes were investigated in this work.

Nanomaterials for energy conversion and storage

Nanostructured materials are advantageous in offering huge surface to volume ratios, favorable transport properties, altered physical properties, and confinement effects resulting from the nanoscale dimensions, and have been extensively studied for energy-related applications such as solar cells, catalysts, thermoelectrics, lithium ion batteries, supercapacitors, and hydrogen storage systems. This review focuses on a few select aspects regarding these topics, demonstrating that nanostructured materials benefit these applications by (1) providing a large surface area to boost the electrochemical reaction or molecular adsorption occurring at the solid-liquid or solid-gas interface, (2) generating optical effects to improve optical absorption in solar cells, and (3) giving rise to high crystallinity and/or porous structure to facilitate the electron or ion transport and electrolyte diffusion, so as to ensure the electrochemical process occurs with high efficiency. It is emphasized that, to further enhance the capability of nanostructured materials for energy conversion and storage, new mechanisms and structures are anticipated. In addition to highlighting the obvious advantages of nanostructured materials, the limitations and challenges of nanostructured materials while being used for solar cells, lithium ion batteries, supercapacitors, and hydrogen storage systems have also been addressed in this review.

Nanostructured conformal hybrid solar cells: a promising architecture towards complete charge collection and light absorption

We introduce hybrid solar cells with an architecture consisting of an electrodeposited ZnO nanorod array (NRA) coated with a conformal thin layer (<50 nm) of organic polymer-fullerene blend and a quasi-conformal Ag top contact (Thin/NR). We have compared the performance of Thin/NR cells to conventional hybrid cells in which the same NRAs are completely filled with organic blend (Thick/NR). The Thin/NR design absorbs at least as much light as Thick/NR cells, while charge extraction is significantly enhanced due to the proximity of the electrodes, resulting in a higher current density per unit volume of blend and improved power conversion efficiency. The NRAs need not be periodic or aligned and hence can be made very simply.

Hierarchical structures consisting of SiO2 nanorods and p-GaN microdomes for efficiently harvesting solar energy for InGaN quantum well photovoltaic cells

We experimentally and theoretically demonstrated the hierarchical structure of SiO(2) nanorod arrays/p-GaN microdomes as a light harvesting scheme for InGaN-based multiple quantum well solar cells. The combination of nano- and micro-structures leads to increased internal multiple reflection and provides an intermediate refractive index between air and GaN. Cells with the hierarchical structure exhibit improved short-circuit current densities and fill factors, rendering a 1.47 fold efficiency enhancement as compared to planar cells.

An efficient broadband and omnidirectional light-harvesting scheme employing a hierarchical structure based on a ZnO nanorod/Si3N4-coated Si microgroove on 5-inch single crystalline Si solar cells

We employ a ZnO nanorod/Si(3)N(4)-coated Si microgroove-based hierarchical structure (HS) for a light-harvesting scheme in 5 inch single crystalline Si solar cells. ZnO nanorods and Si microgrooves were fabricated by a simple and scalable aqueous process. The excellent light-harvesting characteristics of the HS, such as broadband working ranges and omnidirectionality have been demonstrated using external quantum efficiencies and reflectance measurements. The solar cells with the hierarchical surface exhibit excellent photovoltaic characteristics, i.e., a short-circuit current (J(SC)) of 38.45 mA cm(-2), open-circuit voltage of 609 mV and conversion efficiency of 14.04%. As incident angles increase from 0° to 60°, only 5.3% J(SC) loss is achieved by employing the hierarchical surface, demonstrating the enhanced omnidirectional photovoltaic performances, also confirmed by the theoretical analysis. A viable scheme for broadband and omnidirectional light harvesting using the HS employing microscale/nanoscale surface textures on single crystalline Si solar cells has been demonstrated.

Supersensitive, ultrafast, and broad-band light-harvesting scheme employing carbon nanotube/TiO2 core-shell nanowire geometry

We demonstrate a novel, feasible strategy for practical application of one-dimensional photodetectors by integrating a carbon nanotube and TiO(2) in a core-shell fashion for breaking the compromise between the photogain and the response/recovery speed. Radial Schottky barriers between carbon nanotube cores and TiO(2) shells and surface states at TiO(2) shell surface regulate electron transport and also facilitate the separation of photogenerated electrons and holes, leading to ultrahigh photogain (G = 1.4 × 10(4)) and the ultrashort response/recovery times (4.3/10.2 ms). Additionally, radial Schottky junction and defect band absorption broaden the detection range (UV-visible). The concept using metallic core oxide-shell geometry with radial Schottky barriers holds potential to pave a new way to realize nanostructured photodetectors for practical use.

Photon management with core-shell nanowire structures

Antireflective Si/oxide core-shell nanowire arrays (NWAs) were fabricated by galvanic etching and subsequent annealing process. The excellent light-harvesting characteristics of the core-shell NWAs, such as broadband working ranges, omnidirectionality, and polarization-insensitivity, ascribed to the smooth index transition from air to the substrates, have been demonstrated. By tuning core-shell volume ratios, we obtained enhanced light trapping regions implemented in either the planar Si underneath NWAs or the core regions of NWAs, greatly benefiting the geometry design of planar and radial p-n junction cell structures, respectively. This photon management scheme indicates the potential use in nanostructured photovoltaic applications.

Enhancement of light extraction in GaN-based light-emitting diodes using rough beveled ZnO nanocone arrays

A remarkable enhancement of light extraction efficiency in GaN-based blue light-emitting diodes (LEDs) with rough beveled ZnO nanocone arrays grown on the planar indium tin oxide (ITO) layer is reported. The light output power of LEDs with rough beveled ZnO nanocone arrays was increased by about 110% at 20 mA compared with conventional LEDs with planar ITO. The light extraction efficiency of GaN-based LEDs with rough-beveled ZnO nanocones is measured much greater than with smooth-surface hexagonal ZnO nanorods. The light-ray tracing analysis showed that ZnO nanocones with rough surfaces enlarge the light escape cone of GaN-based LEDs and have a greater advantage for extracting light compared with ZnO nanorods.

Fabrication and characterization of silicon wire solar cells having ZnO nanorod antireflection coating on Al-doped ZnO seed layer

In this study, we have fabricated and characterized the silicon [Si] wire solar cells with conformal ZnO nanorod antireflection coating [ARC] grown on a Al-doped ZnO [AZO] seed layer. Vertically aligned Si wire arrays were fabricated by electrochemical etching and, the p-n junction was prepared by spin-on dopant diffusion method. Hydrothermal growth of the ZnO nanorods was followed by AZO film deposition on high aspect ratio Si microwire arrays by atomic layer deposition [ALD]. The introduction of an ALD-deposited AZO film on Si wire arrays not only helps to create the ZnO nanorod arrays, but also has a strong impact on the reduction of surface recombination. The reflectance spectra show that ZnO nanorods were used as an efficient ARC to enhance light absorption by multiple scattering. Also, from the current-voltage results, we found that the combination of the AZO film and ZnO nanorods on Si wire solar cells leads to an increased power conversion efficiency by more than 27% compared to the cells without it.

Solar energy harvesting scheme using syringe-like ZnO nanorod arrays for InGaN/GaN multiple quantum well solar cells

Syringe-like ZnO nanorod arrays (NRAs) synthesized by a hydrothermal method were applied as the light-harvesting layer on InGaN-based multiple quantum well (MQW) solar cells. Theoretical calculations show that the NRAs with an abrupt shrinkage of tip diameter can further suppress surface reflectance in comparison with the flat NRAs. InGaN-based MQW solar cells with the syringe-like NRAs exhibit greatly improved conversion efficiencies by 36%. These results are attributed to the improved flatness of the refractive index profile at the air/device interface, which results in enhanced light trapping effect on the device surface.

Significant efficiency enhancement of hybrid solar cells using core-shell nanowire geometry for energy harvesting

A novel strategy employing core-shell nanowire arrays (NWAs) consisting of Si/regioregular poly(3-hexylthiophene) (P3HT) was demonstrated to facilitate efficient light harvesting and exciton dissociation/charge collection for hybrid solar cells (HSCs). We experimentally demonstrate broadband and omnidirectional light-harvesting characteristics of core-shell NWA HSCs due to their subwavelength features, further supported by the simulation based on finite-difference time domain analysis. Meanwhile, core-shell geometry of NWA HSCs guarantees efficient charge separation since the thickness of the P3HT shells is comparable to the exciton diffusion length. Consequently, core-shell HSCs exhibit a 61% improvement of short-circuit current for a conversion efficiency (η) enhancement of 31.1% as compared to the P3HT-infiltrated Si NWA HSCs with layers forming a flat air/polymer cell interface. The improvement of crystal quality of P3HT shells due to the formation of ordering structure at Si interfaces after air mass 1.5 global (AM 1.5G) illumination was confirmed by transmission electron microscopy and Raman spectroscopy. The core-shell geometry with the interfacial improvement by AM 1.5G illumination promotes more efficient exciton dissociation and charge separation, leading to η improvement (∼140.6%) due to the considerable increase in V(oc) from 257 to 346 mV, J(sc) from 11.7 to 18.9 mA/cm(2), and FF from 32.2 to 35.2%, which is not observed in conventional P3HT-infiltrated Si NWA HSCs. The stability of the Si/P3HT core-shell NWA HSCs in air ambient was carefully examined. The core-shell geometry should be applicable to many other material systems of solar cells and thus holds high potential in third-generation solar cells.

Urchin-aggregation inspired closely-packed hierarchical ZnO nanostructures for efficient light scattering

We reported the enhancement of light scattering in the urchin-aggregation shaped closely-packed hierarchical ZnO nanostructures, fabricated by a simple and scalable process based on the hydrothermal method utilizing the silica microspheres monolayer as a two-dimensional periodic template. From theoretical predictions, the diffuse light scattering is closely related to the size of silica microspheres as light diffusion centers. Moreover, the ZnO nanorod arrays on silica microspheres monolayer provide the further enhancement of light scattering. The experimentally fabricated urchin-aggregation shaped ZnO nanostructures using silica microspheres of 970 nm indicated a high density of ZnO nanorods with a wide bending angle, which led to the largely increased photoluminescence intensity and a high transmittance haze ratio of > 70% in the wavelength range of 400-900 nm in keeping with a high total transmittance. The contact angles of a water droplet on the surface of the samples were also explored.

Ultra-high-responsivity broadband detection of Si metal-semiconductor-metal Schottky photodetectors improved by ZnO nanorod arrays

This study describes a strategy for developing ultra-high-responsivity broadband Si-based photodetectors (PDs) using ZnO nanorod arrays (NRAs). The ZnO NRAs grown by a low-temperature hydrothermal method with large growth area and high growth rate absorb the photons effectively in the UV region and provide refractive index matching between Si and air for the long-wavelength region, leading to 3 and 2 orders of magnitude increase in the responsivity of Si metal-semiconductor-metal PDs in the UV and visible/NIR regions, respectively. Significantly enhanced performances agree with the theoretical analysis based on the finite-difference time-domain method. These results clearly demonstrate that Si PDs combined with ZnO NRAs hold high potential in next-generation broadband PDs.

Highly active and enhanced photocatalytic silicon nanowire arrays

Nanoporous and nonporous three-dimensional silicon nanowire arrays (SiNWAs) prepared with metal-assisted chemical etching method were investigated as photocatalysts in dye photodegradation systematically. In comparison with nonporous SiNWAs, nanoporous SiNWAs have higher surface area, larger pore volume, stronger light absorption and better photocatalytic activity. After the HF-treatment, the photocatalytic activity of all kinds of SiNWAs increased significantly and the nanoporous SiNWAs showed excellent stability. The photocatalytic activity of different types of SiNWAs with hydrogen surface termination can be recovered by HF treatment. This study also reveal that the hydrogen terminated surfaces on silicon nanowires (SiNWs) enhance the performance of SiNWAs by increasing their photocatalytic activity.