Nanometer-scale measurements of electronic states in InAs/GaAs quantum dots

被引：9

作者：

Dasika, V. D. ^{[1
]}

Goldman, R. S. ^{[1
,2
]}

Song, J. D. ^{[3
]}

Choi, W. J. ^{[3
]}

Cho, N. K. ^{[3
]}

Lee, J. I. ^{[3
]}

机构：

[1] Univ Michigan, Dept Elect Engn & Comp Sci, Ann Arbor, MI 48109 USA

[2] Univ Michigan, Dept Mat Sci & Engn, Ann Arbor, MI 48109 USA

[3] Korea Inst Sci & Technol, Nano Device Res Ctr, Seoul 136791, South Korea

来源：

JOURNAL OF APPLIED PHYSICS | 2009年 / 106卷 / 01期

关键词：

gallium arsenide; III-V semiconductors; indium compounds; scanning tunnelling microscopy; semiconductor quantum dots; wetting; WETTING LAYERS; GAAS MATRIX; INAS; INTERDIFFUSION; SEGREGATION; GROWTH; LASER;

D O I：

10.1063/1.3158560

中图分类号：

O59 [应用物理学];

学科分类号：

摘要：

We have investigated the origins of electronic states in individual (uncoupled) quantum dots (QDs) and the surrounding wetting layers (WLs) using a combination of cross-sectional scanning tunneling microscopy (XSTM) and scanning tunneling spectroscopy (STS). XSTM images reveal uncoupled ellipse-shaped QDs with 18 +/- 5 nm (9 +/- 3 nm) major (minor) axes. Room temperature STS spectra reveal a gradient in the effective bandgap within the QDs with smallest values near the QD core and top surfaces. The variations in effective bandgap are apparently dominated by indium composition gradients, with minimal effects due to the QD shape and strain. Indium composition gradients also dominate the effective bandgap variations in the WL.

引用

页数：4

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