Passivation effects on ZnO nanowire field effect transistors under oxygen, ambient, and vacuum environments

Abstract

We investigated the passivation effects on the electrical characteristics of ZnO nanowire field effect transistors (FETs) under the various oxygen environments of ambient air, dry O2, and vacuum. When the ZnO nanowire FET was exposed to more oxygen, the current decreased and the threshold voltage shifted to the positive gate bias direction, due to electrons trapping to the oxygen molecules at the nanowire surface. On the contrary, the electrical properties of the nanowire FET remained unchanged under different environments with passivation by a polymethyl methacrylate layer, which demonstrates the importance of surface passivation for ZnO nanowire-based electronic device applications.

ZnO UV photodetector with controllable quality factor and photosensitivity

“…34 Therefore, in a phototransistor V th proportionally varies with the density of carriers which strongly depends on the surface states, the environment, temperature and the incidence of light. [35][36][37] When one measures the dependence of I sd as a function of the gate voltage for different incident wavelengths (Fig. 2(a)), one can see that under photo-absorption, the photocurrent increases and V th shifts to larger amplitudes.…”

Solution processable multi-channel ZnO nanowire field-effect transistors with organic gate dielectric

“…Ambient instability of ZnO has been ascribed in the literature to the adsorption of oxygen on ZnO surface which depletes the surface of electrons, leading to positive VT shifts in ZnO NW based FETs. [30] Song et al [31] presented some evidence of single ZnO NW FET sensitivity to ambient air, in which positive VT shifts and degradation in I-V curves were observed after devices were exposed to ambient air. The authors demonstrated that passivation of the ZnO NW surface with PMMA can offer a more stable device operation.…”

Investigation of Structural and Electronic Properties of CH3NH3PbI3 Stabilized by Varying Concentrations of Poly(Methyl Methacrylate) (PMMA)

“…Song et al reported on the use of PMMA in passivating surface traps of electronic devices made of ZnO nanaowires. Passivated ZnO nanowire FET S maintained their electrical properties under different environmental conditions while carrier concentration and mobility of un-passivated FETs were significantly influenced by the environmental [13].…”

“…PMMA is an amorphous, environmentally friendly, and cost effective polymer used in many applications, such as in making aircraft windows. Many researchers have reported on the passivating role of PMMA on perovskite by filling pinholes and surface traps [13][14][15]. Song et al reported on the use of PMMA in passivating surface traps of electronic devices made of ZnO nanaowires.…”