Electrical characteristics and rectification performance of wet chemically synthesized vertically aligned n-ZnO nanowire/p-Si heterojunction

Abstract

Vertically well-aligned n-ZnO nanowire (NW) thin films were deposited onto p-Si substrates by a two-step wet chemical technique to form a p–n heterojunction diode. The morphological and structural characteristics of the ZnO NW performed by scanning electron microscopy (SEM) and x-ray diffraction (XRD) revealed well-aligned h-ZnO NW with a wurtzite structure. A direct optical band gap of 3.30 eV was calculated from the transmittance trace obtained using a UV–VIS–NIR spectrophotometer. The electrical characteristics of the heterojunction diode were studied by capacitance–voltage (C–V) measurement at room temperature, and current–voltage–temperature (I–V–T) measurements performed in the 300–400 K range. The C–V measurements yield a carrier concentration of 1.3 × 1016 c.c.−1 for the ZnO NW thin film. The ideality factor (n) was found to decrease, while the barrier height (φ b0) increased with the increase in temperature, when calculated using a thermionic emission model from the non-linear I–V–T plots. The series resistance (R s) calculated by the Cheung–Cheung method decreased with the increase in temperature. The mean barrier height (0.718 eV) and modified Richardson constant (28.4 A cm−2 K−2) calculated using a Gaussian distribution of barrier heights (considering barrier height inhomogeneity) were closer to the theoretical value than those calculated from the linear approximation of the ln(I s/T 2) versus 1000/T plot. The variation of the density of interface states with interface state energy was also studied. The n-ZnO NW/p-Si heterojunction diode performed very good half wave rectification in the frequency range 50 Hz–10 kHz, when a sinusoidal ac voltage of amplitude 4.5 V was applied across it.

Electrical Characterization of Si/ZnO Nanorod PN Heterojunction Diode

“…e values of series resistances are 0.77 KΩ, 0.73 KΩ, and 0.75 KΩ obtained by different methods for our heterojunction. ese values are on higher side however less than the values of 3.2 KΩ and 2.69/2.70 KΩ reported by [30,33], respectively. Barrier height and ideality factor are in agreement with reported values.…”

A Photodetector Based on p-Si/n-ZnO Nanotube Heterojunctions with High Ultraviolet Responsivity

“…Relevant energy levels of the materials used in this device structure are shown in Figure b. The valence band (VB) and conduction band (CB) of Si are −5.17 and −4.05 eV, respectively, while the VB and CB of ZnO are −7.71 and −4.35 eV, respectively. , Upon 365 nm UV illumination, photoinduced carriers are generated in ZnO NTs. The energy band alignment of the device ensures that electrons are injected from the photosensitive ZnO NTs and are collected by the ITO electrode, while the VB holes reach the Ag electrode through the p-Si substrate.…”

Photoelectrochemical study of carbon-modified p-type Cu2O nanoneedles and n-type TiO2−x nanorods for Z-scheme solar water splitting in a tandem cell configuration

“…14,23,36,37 The efficiency of this tandem system is evaluated by placing the two photoelectrodes side by side (parallel) or one in the front of the other (tandem). On the other hand, since p-n heterojunctions have also received great interests due to their potential use in optoelectronic devices such as biosensors and photodiodes; [38][39][40] in the present work, we also analyzed the electrical characteristics of a p-C/Cu 2 O NNskn-TiO 2Àx NRs heterojunction photodiode behavior to further understand the charge transfer mechanism in the absence of water. 0.0254 mm thick) were purchased from Alfa Aesar Co. Cu foils (1.5 cm  1.5 cm) were rst ultrasonically degreased in acetone, detergent water, and deionized water, respectively.…”