Electrical Characterization of Si/ZnO Nanorod PN Heterojunction Diode

Sadia Muniza Faraz,Omer Nur,Naveed Ul Hassan Alvi,Qamar Ul Wahab,Wakeel Shah

doi:10.1155/2020/6410573

Abstract

The electrical characterization of p-Silicon (Si) and n-Zinc oxide (ZnO) nanorod heterojunction diode has been performed. ZnO nanorods were grown on p-Silicon substrate by the aqueous chemical growth (ACG) method. The SEM image revealed high density, vertically aligned hexagonal ZnO nanorods with an average height of about 1.2 μm. Electrical characterization of n-ZnO nanorods/p-Si heterojunction diode was done by current-voltage (I-V), capacitance-voltage (C-V), and conductance-voltage (G-V) measurements at room temperature. The heterojunction exhibited good electrical characteristics with diode-like rectifying behaviour with an ideality factor of 2.7, rectification factor of 52, and barrier height of 0.7 V. Energy band (EB) structure has been studied to investigate the factors responsible for small rectification factor. In order to investigate nonidealities, series resistance and distribution of interface state density (NSS) below the conduction band (CB) were extracted with the help of I-V and C-V and G-V measurements. The series resistances were found to be 0.70, 0.73, and 0.75 KΩ, and density distribution interface states from 8.38 × 1012 to 5.83 × 1011 eV−1 cm−2 were obtained from 0.01 eV to 0.55 eV below the conduction band.

Highlights

Zinc oxide (ZnO) is a promising and environment friendly semiconductor with a large exciton binding energy (60 meV) and a direct and wideband gap (3.37 eV)
The nanorods were not perfectly aligned on the substrate, they had a tendency to grow vertical on the substrate with an almost uniform distribution. e standard aspect ratio (SAR) of 4.66–7.77 has been obtained by dividing the length of rods with its diameter which is in agreement with reported values for hydrothermally grown ZnO nanorods [20, 21]
Current-voltage (I-V) characteristics of the Si/ZnO pn heterojunction have been studied at room temperature for a voltage range from–10 to +10 V as shown in Figure 3; inset shows the schematic of Si/ZnO heterojunction

Summary

Introduction

Zinc oxide (ZnO) is a promising and environment friendly semiconductor with a large exciton binding energy (60 meV) and a direct and wideband gap (3.37 eV). It has superior physical properties such as high breakdown electric field, high electron saturation velocity; radiation tolerance, and thermal conductivity [1], which enable it for making high-power and high-temperature devices. Homojunctions of ZnO are difficult to realize because reproducible p-type with desired hole concentration without diminution is still under research [6, 7]. Heterojunctions of ZnO are realized with various semiconductors most commonly Si, GaN, and SiC for the fabrication of LEDs, Photodetectors, solar cells, biosensors, etc. Heterojunctions of ZnO are realized with various semiconductors most commonly Si, GaN, and SiC for the fabrication of LEDs, Photodetectors, solar cells, biosensors, etc. [8,9,10,11]

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Results

Conclusion