Wide spectral photoresponse of template assisted out of plane grown ZnO/NiO composite nanowire photodetector

Abstract

Zinc oxide (ZnO) one-dimensional nanostructures are extensively used in ultra-violet (UV) detection. To improve the optical sensing capability of ZnO, various nickel oxide (NiO) based p–n junctions have been employed. ZnO/NiO heterojunction based sensing has been limited to UV detection and not been extended to the visible region. In the present work, p-NiO/n-ZnO composite nanowire (NW) heterojunction based UV-visible photodetector is fabricated. A porous anodic aluminum oxide template based electrochemical deposition method is adopted for well separated and vertically aligned growth of composite NWs. The photoresponse is studied in an out of plane contact configuration. The fabricated photodetector shows fast response under UV-visible light with a rise and decay time of tens of ms. The wide spectral photoresponse is analyzed in terms of conduction from defect states of ZnO and interfacial defects during p–n junction formation. Light interaction with heterojunction along the length of the composite NW results in enhanced visible photoresponse of the detector and is further supported by simulation.

Ag Nanowire-Plasmonic-Assisted Charge Separation in Hybrid Heterojunctions of Ppy-PEDOT:PSS/GaN Nanorods for Enhanced UV Photodetection

“…Further, we next present the detailed comparison of rising and falling times of the photoresponse curves of all devices, as displayed in Figure . The estimated rising and falling times of PDs are given by the following equations, respectively where the term I dark refers to the device dark current, t is the UV source on and off times, A 1 , A 2 and B 1 , B 2 are the scaling constants, and τ r1, τ r2 and τ f1 , τ f2 stand for the rising time and falling time constants, respectively.…”

Integration of an Electron Transport Layer and a p‐n Heterojunction in a ZnO photoanode for Photoelectrochemical Water Oxidation

“…reported a novel efficient strategy for designing a p‐n type nano heterojunction photoanode to improve the water splitting efficiency by growing low band‐gap p‐CuFeO 2 nanolayers on n‐ZnO nanorods through an easy and scalable electrochemical route [38] . So far, there are still many problems in the elaborate construction of micro‐nano structures for ZnO‐based semiconductors, such as phase interface defects, long‐range transport of photogenerated carriers in multi‐structures, and slow surface water oxidation kinetics [39–42] …”

“…[38] So far, there are still many problems in the elaborate construction of micro-nano structures for ZnO-based semiconductors, such as phase interface defects, long-range transport of photogenerated carriers in multi-structures, and slow surface water oxidation kinetics. [39][40][41][42] In this work, a ZnO photoanode is built with a nanosheet cluster micro-nano structure, where TiO 2 in the bottom surface is applied to reduce the interface defect between the FTO substrate and ZnO, and NiO in the top surface is introduced to construct a NiO/ZnO p-n heterojunction structure. The FTO/ TiO 2 /ZnO/NiO photoanode exhibits the largest photocurrent density with a photocurrent density of 1.91 mA/cm 2 at 1.23 V RHE , which is 194 % higher than that of the pure ZnO photoanode (0.65 mA/cm 2 ).…”

Pd Nanoparticle Adsorption ZnO Nanorods for Enhancing Photodetector UV-Sensing Performance

“…These materials have been used in light-emitting diodes, sensors, transistors, lasers, displays, photodetectors, highpowered devices, solar cells, memory and so on [1][2][3][4][5][6][7][8]. Given their wide bandgap, inorganic oxide-based semiconductor materials, such as In2O3 (3.7 eV), Ga2O3 (4.9 eV), ZnO (3.37 eV), NiO (3.9 eV) and WO3 (2.8 eV) have been utilised for optoelectronic devices [9][10][11][12]. Among these materials, ZnO is a popular inorganic substance owing to its excellent characteristics, such as high exciton binding energy (60 meV), high stability of thermal and chemical, high mechanical strength, simple processing, nontoxicity, low cost and various nanostructures (e.g.…”