New Insights into Mechanism of Surface Reactions of ZnO Nanorods During Electrons Beam Irradiation

Abstract

This study provides new insight into mechanisms of ionic reactions on the surface of ZnO nanorod networks, which could result in enhanced performance in optical or molecular sensors. The current- voltage characteristics of ZnO nanorod network devices exhibit typical nonlinear behavior in air, which implies the formation of a Schottky barrier when metals are used as contacts. The conductance of the device increased significantly in vacuum, which can be explained by the desorption of hydroxyl groups at very low pressure. While physisorbed water or oxygen-related ions can detach from the ZnO surface during evacuation, exposure to high energy in the electron beam is believed to detach the chemisorbed anions of O- and O-2 from the surface of ZnO nanorods, which releases more electrons into the channel. The increase in available electrons enhances the conductance of the ZnO nanorods. Slow initialization of the conductance under ambient conditions indicates that the ionic re-adsorption is inactive under these conditions. Thus, the electron irradiation process can be used to reset the surface ionic molecules on metal oxide nano-structures by tuning the surface potential prior to the passivation process.

High Sensitivity Humidity Sensors Based on Zn1−xSnxO Nanostructures and Plausible Sensing Mechanism

“…[ 7 ] Related studies have shown that 1D ZnO nanostructures have excellent sensing properties, such as high sensitivity, fast response/recovery, and have been used in humidity detection fields. [ 8–14 ]…”

“…[7] Related studies have shown that 1D ZnO nanostructures have excellent sensing properties, such as high sensitivity, fast response/recovery, and have been used in humidity detection fields. [8][9][10][11][12][13][14] In order to meet the actual demand of production and life, the sensing characteristics of ZnO sensors need to be further improved. The chemical sensing ability of metal oxide materials can be enhanced by increasing the specific surface area and improving the surface state.…”

Characteristics of Ultraviolet Photodetector Based on Li-doped ZnO Nanorods

“…Moreover, each ZnO freestanding NR can accelerate oxygen desorption and adsorption. (15,16) In the dark, the oxygen molecules adsorb onto the ZnO NR surface by capturing free electrons. Upon irradiating UV light, oxygen molecules desorb from the surface, leading to an increased free carrier concentration and a reduced Schottky barrier height.…”

Improving ZnO Nanorod Humidity Sensors with Pt Nanoparticle Adsorption

“…[8][9][10][11][12][13][14][15][16][17][18] ZnO has been widely used in ultraviolet photosensors, light-emitting diodes, varistors, laser diodes, field emission devices, and optical resonators. [19][20][21][22][23][24][25][26][27][28][29][30] ZnO nanostructures can be prepared using various methods, such as vapor-liquid-solid, chemical vapor deposition, and hydrothermal method. The hydrothermal method obvious evident advantages, such as nanostructures with uniform morphology and homogeneous size, high yield, controllability, simplicity, low temperature requirement, and low cost.…”