Indium enrichment in Ga1-xInxP self-assembled quantum dots

Quantum dots of Ga1-xInxP on GaP (001) have been grown by low-pressure meta lorganic vapor phase epitaxy at 650 degreesC with varying (Ga,In)P coverage s. The quantum dots were extensively characterized by transmission electron microscopy (TEM), atomic force microscopy, energy dispersive x-ray spectro scopy, and temperature-dependent photoluminescence spectroscopy (PL). With increasing coverage the dots develop first as flat, extended hills with mor e or less pronounced {113} facets. Subsequently, on top of these hills, sma ller, well-faceted, In-rich dots are formed. The PL intensity emitted from these dots is first constant and then increases with increasing temperature towards a maximum at about 200 K before it decreases. We present a model w hich explains the experiments, assuming In-rich dots surrounded by Ga-rich barriers. No evidence of alloy ordering was found in the TEM measurements. (C) 2000 American Institute of Physics. [S0021-8979(01)02201-0].