Growth-Temperature Dependence of Wetting Layer Formation in High Density InGaAs/GaAs Quantum Dot Structures Grown by Droplet Epitaxy

We present a study of the growth-temperature-dependent wetting layer formation in self-assembled InGaAs/GaAs quantum dot structures formed by droplet epitaxy at elevated growth temperatures up to 500 °C. The energies of electron heavy-hole and light-hole transitions of the InGaAs wetting layer is in...

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Published inJapanese Journal of Applied Physics Vol. 51; no. 8; pp. 085501 - 085501-4
Main Authors Zuerbig, Verena, Bugaew, Natalia, Reithmaier, Johann Peter, Kozub, Micha$ł$, Musia$ł$, Anna, S\{e}k, Grzegorz, Misiewicz, Jan
Format Journal Article
LanguageEnglish
Published The Japan Society of Applied Physics 01.08.2012
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Summary:We present a study of the growth-temperature-dependent wetting layer formation in self-assembled InGaAs/GaAs quantum dot structures formed by droplet epitaxy at elevated growth temperatures up to 500 °C. The energies of electron heavy-hole and light-hole transitions of the InGaAs wetting layer is investigated by contactless electroreflectance spectroscopy. A clear indication of a strong growth-temperature influence on the wetting layer morphology is observed. At the lowest growth temperature no wetting layer could be detected at all. The influence of the substrate temperature on structural and optical properties of the dots is also discussed.
Bibliography:Cross-section illustration of the grown structures. AFM images ($1\times 1$ μm 2 ) of QDs formed by DE at (a) 410, (b) 450, and (c) 500 °C and their histograms of the QD height distribution. Low-temperature PL spectra (10 K) of QDs formed by DE (a) at 410, 450, and 500 °C with low excitation power density (52 W/cm 2 ) and (b) at 500 °C with low (50 W/cm 2 ) and high excitation power density (500 W/cm 2 ). The arrow in (b) indicates the WL PL emission at high excitation power density. Room-temperature CER spectra of QD structures grown by DE at (a) 410, (b) 450, and (c) 500 °C. The arrows indicate the transition peaks of GaAs and the heavy-hole- and light-hole-related transitions of the WL.
ISSN:0021-4922
1347-4065
DOI:10.1143/JJAP.51.085501