Study on ultra-high sensitivity piezoelectric effect of GaN micro/nano columns

Jianbo Fu,Hua Zong,Haixia Zhang,Xiaodong Hu

doi:10.1186/s40580-019-0203-4

Jianbo Fu, Hua Zong + Show 2 more

Open Access

https://doi.org/10.1186/s40580-019-0203-4

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Journal: Nano convergence	Publication Date: Oct 22, 2019
Citations: 8	License type: open-access

Affiliation: Institute of Microelectronics, Peking University

Abstract

High-quality GaN micro/nano columns were prepared with self-organized catalytic-free method. Young’s modulus of GaN nanocolumns were measured under both compressive stress and tensile stress. It was found that the Young’s modulus decreases with the increasing of nanocolumn diameter due to the increase of face defect density. Furthermore, we measured the piezoelectric properties and found that there was a 1000-fold current increase under a strain of 1% with a fixed bias voltage of 10 mV. Based on the Schottky Barrier Diode model, we modified it with the effect of polarization charge, image charge and interface state to analyze the experiment results which reveals that the strong piezopolarization effect plays an important role in this phenomenon. Therefore, the GaN nanocolumns has a great prospect to be applied in high-efficiency nanogenerators and high-sensitivity nanosensors.

Highlights

With the development of wearables and electronic skin in recent years, it is an urgent need to improve the performance of sensors and power supply devices while reducing their sizes
3.1 Mechanical properties of GaN micro/nano columns Young’s modulus is a measure of the stiffness for an elastomer which is defined as the ratio between stress and strain in the range applicable to Hooke’s law
4 Conclusion In-situ compression modulus tests were performed along C-axis of GaN nanocolumns in the scanning electron microscope (SEM) using Hysitron’s mechanical sample stage

Summary

Introduction

With the development of wearables and electronic skin in recent years, it is an urgent need to improve the performance of sensors and power supply devices while reducing their sizes. Piezoelectric effect has been studied a lot as one of the major branches of nanogenerators and nanosensors for its excellent performance. It is believed that due to the strong piezoelectric effect of ZnO, the contact potential between the nanowire and the silver gel changes when the stress is applied. Compared with ZnO materials, the advantage of higher piezoelectric coefficient [10] makes GaN more suitable for nanosensor and nanogenerator [11,12,13]. Due to the difficulty in the preparation of high-quality GaN nanocolumns, there is few works on the mechanical and piezoelectric properties of micro/nano columns. High-quality GaN micro/nano columns were grown, and their mechanical properties and piezoelectric properties were studied. It is found that there is an ultra-high sensitivity piezoelectric effect in these GaN micro/nano columns. Fu et al Nano Convergence (2019) 6:33 application prospect in piezoelectric nanosensors and nanogenerators [18, 19]

Self‐organized catalytic‐free growth of GaN nanocolumns

Results and discussion

Conclusion