Silicon nanowire–silver indium selenide heterojunction photodiodes

Abstract

Structural and optoelectronic properties of silicon (Si) nanowire-silver indium selenide (AgInSe2) thin film heterojunctions were investigated. The metal-assisted etching method was employed to fabricate vertically aligned Si nanowire arrays. Stoichiometric AgInSe2 films were then deposited onto the nanowires using co-sputtering and sequential selenization techniques. It was demonstrated that the three-dimensional interface between the Si nanowire arrays and the AgInSe2 thin film significantly improved the photosensitivity of the heterojunction diode compared to the planar reference. The improvements in device performance are discussed in terms of interface state density, reflective losses and surface recombination of the photogenerated carriers, especially in the high-energy region of the spectrum.

Optical photoresponse of CuS–n-Si radial heterojunction with Si nanocone arrays fabricated by chemical etching

“…This corroborates the efficient separation of photo-generated electrons and holes in the depletion region by a built-in field even for the unbiased radial heterojunction device. The peak responsivity value of our nanocone device at zero bias is much higher than that recently reported for radial heterojunctions fabricated on Si nanowires e.g., Si-CdS 23 (0.1 A W À1 ) and Si-AgInSe 2 53 (0.11 A W À1 ). The spectral response consists of several broad peaks, as due to the absorption region of CuS (B550 nm), porous nature of nanocones (B600-750 nm) and self absorption region of Si.…”

Photovoltaic performance of Gallium-doped ZnO thin film/Si nanowires heterojunction diodes

“…3D nature of Si NWs and antireflective and light trapping effects by NW arrays could contribute to the obtained rectification ratio. Furthermore, enhanced interfacial area and nucleation sites on the surfaces of the Si NWs could minimise the structural disorders (dislocations and/or crystal defects) in complementary Ga-doped ZnO thin films, leading to stress relaxation as a result of the highly flexible NWs [21]. Important diode parameters such as ideality factor (n), dark saturation current and barrier height were obtained from the measured I-V characteristics of the NWs-based heterojunction devices under dark conditions.…”

“…As an active component, Si nanowires could be employed in both homojunction and heterojunction device fabrications. It was demonstrated that Si NWs-based three-dimensional (3D) or radial heterojunction devices would offer significant advantages and better performance when compared to the planar counterparts [20,21]. Architecture of these devices consists of 1D Si NWs and a suitable organic or inorganic semiconductor substance that can be integrated with NWs in order to construct nano-sized p-n junctions.…”

“…Recently, several heterojunction concepts have been introduced and different complementary organic or inorganic semiconductors have been utilised in order to investigate the potential applications of Si NWs [20,21,24,25]. Among the wide bandgap semiconductor materials, zinc oxide (ZnO), an inherent n-type semiconductor, has attracted a great deal of interest for next-generation electronic and optoelectronic devices including photovoltaics, light-emitting diodes and photodetectors [26][27][28][29][30][31][32][33][34].…”

Low Cost Fabrication of Si NWs/CuI Heterostructures

“…A crucial aspect for the realization of multifunctional devices is to combine the properties of different materials, such as absorption, light emission and electrical conduction, in order to improve the overall response of a device [ 30 , 31 , 33 , 34 , 35 , 36 , 37 , 38 , 39 ]. Due to their very large aspect ratio and their physical properties, Si NWs realized by MACE stand up as a promising platform for novel heterostructures with great impact for optoelectronics and photovoltaics.…”