Berlin 2008 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 44: Quantum dots and wires: preparation and characterization II

HL 44.1: Talk

Thursday, February 28, 2008, 16:45–17:00, EW 201

Investigation of MOVPE InN quantum dot growth by variation of temperature , V/III ratio and ammonia stabilisation flow — •Simon Ploch, Christian Meissner, Markus Pristovsek, and Michael Kneissl — Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstrasse 36, EW6-1, D-10623 Berlin, Germany

Despite their unique electronic and optical properties very little attention has been devoted to the growth of InN- nanostructures. Because of its bandgap in the range of 0.7 eV InN is an interesting candidate for lasers and LED emitting in the infrared spectral range. So far most InN quantum dots are grown in MBE. To prevent the formation of metalic Indium, very high V/III ratios in the range of 300,000 were used in the InN growth. We present our growth studies of InN quantum dots on GaN investigated by in-situ spectroscopic ellipsometry. As allready shown, we were abel to realize 8-10 ML high 3D structures with a mean hight of 1.7 nm, a mean diameter of 16.5 nm and a density of 2.1011 /cm* . The InN QDs were grown in a N2 atmosphere at 100 mbar, with a V/III ratio of 15,000, the time was 60s. By increasing the V/III ratio from 5,000 to 20,000 we observed a decrease of the growth rate, which can be explained by layer desorption due to reactive hydrogen from ammonia. It should be noted that we were able to obtain high cristaline quality InN QD at low V/III ratios in the range of 5,000 which corespondes with a short growth time compareable to InAs QD growth conditions. An ammonia stabilisation flow shows benefit effects on the InN quantum dot composition due