Metalorganic chemical vapor deposition growth of InAs/GaSb type II superlattices with controllable As x Sb1-xinterfaces

Li-Gong Li,Xiao-Ling Ye,Shu-Man Liu,Tao Yang,Li-Jun Wang,Bo Xu,Feng-Qi Liu,Shuai Luo,Zhan-Guo Wang

doi:10.1186/1556-276x-7-160

Abstract

InAs/GaSb type II superlattices were grown on (100) GaSb substrates by metalorganic chemical vapor deposition (MOCVD). A plane of mixed As and Sb atoms connecting the InAs and GaSb layers was introduced to compensate the tensile strain created by the InAs layer in the SL. Characterizations of the samples by atomic force microscopy and high-resolution X-ray diffraction demonstrate flat surface morphology and good crystalline quality. The lattice mismatch of approximately 0.18% between the SL and GaSb substrate is small compared to the MOCVD-grown supperlattice samples reported to date in the literature. Considerable optical absorption in 2- to 8-μm infrared region has been realized.PACS: 78.67.Pt; 81.15.Gh; 63.22.Np; 81.05.Ea

Highlights

InAs/GaSb superlattices (SLs) are important for longwavelength infrared (IR) applications because of their broken gap type II band alignment with the conduction band minimum of InAs lying below the valence band maximum of GaSb
Quantum well IR photodetectors (QWIPs) [5,6,7] have exhibited a number of potential advantages including highly uniform and well-controlled epitaxy growth, but their quatum efficiency cannot compete with HgCdTe photodiode due to the fact that optical transition is forbidden for normal incidence of light
New nanostructured IR photodectors based on quantum dots have been investigated intensively to outperform quantum well IR (QWIP) since they are intrinsic sensitive to

Summary

Introduction

InAs/GaSb superlattices (SLs) are important for longwavelength infrared (IR) applications because of their broken gap type II band alignment with the conduction band minimum of InAs lying below the valence band maximum of GaSb. The SL structures provide the possibility to have both high absorption efficiency as reached with HgCdTe and high uniform as reached with QWIPs. So far, high-quality InAs/GaSb materials have been grown by molecular beam epitaxy (MBE) [11,12,13].

Results

Conclusion