Structural and optical properties of indium-rich InGaN islands

Abstract

Indium-rich InxGa1-xN islands (x >= 0.87) grown by metalor-ganic chemical vapor deposition at growth temperatures ranging from 550-750 degrees C were investigated. With the increasing growth temperature, the InGaN dot size increases while the dot density decreases due to the enhanced surface migration of In/Ga adatoms at elevated temperatures. In addition, the compositiom of InGaN-islands was also found to be varied with the growth temperature. At lower growth temperatures, a higher Ga content can be achieved due to the relatively lower migration ability of Ga adatoms. At higher growth temperatures, the deposited InGaN material tend to decompose into In-rich islands and a thin Ga-rich layer, Photoluminescence investigations show that these In-rich islands exhibit a near-infrared emission band . For samples grown at higher temperatures a visible emission band was also observed. The visible emission band may arise from defect hands introduced during the formation of Ga-rich InGaN layer. (c) 2008 WILEY-VCH Veriag GmbH & Co. KGaA, Weinheim.