Gold and ZnO-Based Metal-Semiconductor Network for Highly Sensitive Room-Temperature Gas Sensing.

Renyun Zhang,Joel Ljunggren,Magnus Hummelgård,Håkan Olin

doi:10.3390/s19183815

Abstract

Metal-semiconductor junctions and interfaces have been studied for many years due to their importance in applications such as semiconductor electronics and solar cells. However, semiconductor-metal networks are less studied because there is a lack of effective methods to fabricate such structures. Here, we report a novel Au–ZnO-based metal-semiconductor (M-S)n network in which ZnO nanowires were grown horizontally on gold particles and extended to reach the neighboring particles, forming an (M-S)n network. The (M-S)n network was further used as a gas sensor for sensing ethanol and acetone gases. The results show that the (M-S)n network is sensitive to ethanol (28.1 ppm) and acetone (22.3 ppm) gases and has the capacity to recognize the two gases based on differences in the saturation time. This study provides a method for producing a new type of metal-semiconductor network structure and demonstrates its application in gas sensing.

Highlights

The metal-semiconductor (M-S) structure [1,2] is one of the most important structures in semiconductor devices such as photodetectors [3]
The ZnO nanowires grown on gold particles after 2, 15 and 20 min were imaged using scanning electron microscope (SEM)
The reaction of gas molecules occurs less because the absorbed oxygen is not in the form of O− ; the signal change is considered mainly due to the absorption of the gas molecules on the ZnO nanowires, which leads to the change of the Fermi level, which is an important factor of the Sensors 2019, REVIEW

Summary

Introduction

The metal-semiconductor (M-S) structure [1,2] is one of the most important structures in semiconductor devices such as photodetectors [3]. In addition to M-S and M-S-M structures, there is another M-S network [(M-S)n ] structure in which semiconductor nanowires are connected by a metal particle-forming network. Such a structure is less studied because of the lack of an effective and efficient method to fabricate it. The first step is to deposit a gold nanobelt film on a SiO2 wafer to grow the Au–ZnO (M-S). Were grown using evaporation-induced particles with sizes ranging from to nm formed Such gold particles catalyze growth of self-assembly method that has been reported previously [11]. A gas sensor was the deposited nanobelt film and the sensors on arethe given in the (M-S)

Growth of a Gold Nanobelt Pattern

Gas Sensing

Results and Discussion

Sensing Ethanol and Acetone Gases

Conclusions