Effect of Al2O3 Buffer Layers on the Properties of Sputtered VO2 Thin Films

Dainan Zhang,Tianlong Wen,Ying Xiong,Qiye Wen,Donghong Qiu

doi:10.1007/s40820-017-0132-x

Dainan Zhang, Tianlong Wen + Show 3 more

Open Access

https://doi.org/10.1007/s40820-017-0132-x

Copy DOI

Abstract

VO2 thin films were grown on silicon substrates using Al2O3 thin films as the buffer layers. Compared with direct deposition on silicon, VO2 thin films deposited on Al2O3 buffer layers experience a significant improvement in their microstructures and physical properties. By optimizing the growth conditions, the resistance of VO2 thin films can change by four orders of magnitude with a reduced thermal hysteresis of 4 °C at the phase transition temperature. The electrically driven phase transformation was measured in Pt/Si/Al2O3/VO2/Au heterostructures. The introduction of a buffer layer reduces the leakage current and Joule heating during electrically driven phase transitions. The C–V measurement result indicates that the phase transformation of VO2 thin films can be induced by an electrical field.

Highlights

VO2 thin films have generated a considerable interest among scientists over the past decades owing to their nearroom-temperature phase transformation [1]
Al2O3 thin films deposited via plasma-enhanced atomic layer deposition (PEALD) were dense, smooth, with a clear interface, and high dielectric constant (i.e., k of approximately 8.8)
The quality of the VO2 thin film was significantly improved by depositing it on the Al2O3 buffer layer

Summary

Introduction

VO2 thin films have generated a considerable interest among scientists over the past decades owing to their nearroom-temperature phase transformation [1]. VO2 thin films changes by three to five orders of magnitude during this phase transition. The metal-to-insulator (MIT) transition has been utilized in a variety of electronic devices such as electromagnetic wave modulators, switches [7,8,9,10], and holographic storage [11]. VO2 thin films have been used for terahertz (THz)-wave devices [7]. In 2010, VO2 nanowires were deposited on glass substrates using photolithography and magnetron sputtering and used for the thermal modulation of THz waves by Wen et al [7]. The research results showed that the transmittance of THz waves reduced by 65% after traveling through VO2 nanowire arrays during the MIT transition [7]

Methods

Results

Conclusion