Negative Differential Resistance in GaN/AlN Heterostructure Nanowires

Andy Shih,Zetian Mi,Saeed Fathololoumi,Binh Le Huy,Songrui Zhao,Ishiang Shih,Hieu Pham Trung Nguyen

doi:10.11159/ijtan.2012.016

Abstract

III-V semiconductor nanowire heterostructures have experienced great progress in numerous midand far-infrared ranges. In this work, the electrical properties of GaN/AlN nanowire heterostructures, oriented along the [0001] polar direction and grown vertically on a Si substrate by molecular beam epitaxy, were studied in the context of resonant tunneling. The negative differential resistance was observed in I-V measurements at room temperature and at 78 K for single nanowire devices, confirming the presence of resonant tunneling through AlN barriers. A peak-to-valley ratio of 1.4 was achieved. Effects of different doping profiles have been investigated, showing slight improvement of the resonant tunneling in the presence of silicon doping. This work represents a preliminary step in developing GaN nanowire based intersubband devices for far-infrared and telecom wavelength lasers and photodetectors.

Highlights

The transport properties of semiconductor multiple quantum well (MQW) heterostructures was first studied by Esaki and Tsu (1970)
negative differential resistance (NDR) is a property that manifests itself in the current-voltage (I-V) characteristics where the rate of change goes from positive to negative as the voltage across the device increases
It has been shown that a non-polar orientation should improve resonant tunneling when compared to a polar one, and that AlN barriers, compared to AlGaN ones, will result in higher peakto-valley ratios (Carnevale et al, 2012)

Summary

Introduction

The transport properties of semiconductor multiple quantum well (MQW) heterostructures was first studied by Esaki and Tsu (1970). NDR is a property that manifests itself in the current-voltage (I-V) characteristics where the rate of change goes from positive to negative as the voltage across the device increases This is explained through the breaking and creation of resonance between the finite states inside the quantum wells and the conduction band in the emitter side as a bias is applied (Sun, 1998). It has been shown that a non-polar orientation should improve resonant tunneling when compared to a polar one, and that AlN barriers, compared to AlGaN ones, will result in higher peakto-valley ratios (Carnevale et al, 2012) This absence of reproducibility has been largely attributed to the charge trapping at dislocation sites (Golka et al, 2006). We report the negative differential resistance in GaN/AlN multiple quantum well heterostructure nanowires

Fabrication and Results

Conclusion