In situ accurate control of 2D-3D transition parameters for growth of low-density InAs/GaAs self-assembled quantum dots

Mi-Feng Li,Ying Yu,Xiang-Jun Shang,Hai-Qiao Ni,Zhi-Chuan Niu,Ji-Fang He,Yan Zhu,Li-Juan Wang

doi:10.1186/1556-276x-8-86

Abstract

A method to improve the growth repeatability of low-density InAs/GaAs self-assembled quantum dots by molecular beam epitaxy is reported. A sacrificed InAs layer was deposited firstly to determine in situ the accurate parameters of two- to three-dimensional transitions by observation of reflection high-energy electron diffraction patterns, and then the InAs layer annealed immediately before the growth of the low-density InAs quantum dots (QDs). It is confirmed by micro-photoluminescence that control repeatability of low-density QD growth is improved averagely to about 80% which is much higher than that of the QD samples without using a sacrificed InAs layer.

Highlights

Single self-assembled semiconductor quantum dots (QDs) are of increasing interest due to their applications in lowthreshold lasers [1], single-photon and entangled photon sources [2,3], quantum computing, and quantum information processing [4,5]
For sample 9 (Table 1), the critical thickness of InAs was grown, but the micro-PL and Fourier-PL were envelop curves at 80 K (Figure 3a,b), which demonstrated that the density of QDs was too high for single-photon source devices
We have proposed a method of introducing a sacrificial InAs layer to determine in situ the 2D-3D critical condition as a spotty pattern appears in reflection high-energy electron diffraction (RHEED)

Summary

Introduction

Single self-assembled semiconductor quantum dots (QDs) are of increasing interest due to their applications in lowthreshold lasers [1], single-photon and entangled photon sources [2,3], quantum computing, and quantum information processing [4,5]. To increase the repeatability and to obtain good single-photon characteristics, we investigated a growth technique to obtain in situ the critical deposition in 2D-3D growth transition and slightly change the critical conditions to achieve InAs QDs with good single-photon characteristics. The success ratio is improved averagely to about 80% which is much higher than that of the traditional QD samples (less than 47%)

Methods

Results

Conclusion