Phase separation suppression in InGaN epitaxial layers due to biaxial strain

Universidade de São Paulo, Instituto de Fı´sica, Caixa Postal 66318, 05315-970 São Paulo, SP, Brazil
Applied Physics Letters (Impact Factor: 3.52). 03/2002; DOI: 10.1063/1.1436270
Source: IEEE Xplore

ABSTRACT Phase separation suppression due to external biaxial strain is observed in In x Ga 1-x N alloy layers by Raman scattering spectroscopy. The effect is taking place in thin epitaxial layers pseudomorphically grown by molecular-beam epitaxy on unstrained GaN(001) buffers. Ab initio calculations carried out for the alloy free energy predict and Raman measurements confirm that biaxial strain suppress the formation of phase-separated In-rich quantum dots in the In x Ga 1-x N layers. Since quantum dots are effective radiative recombination centers in InGaN, we conclude that strain quenches an important channel of light emission in optoelectronic devices based on pseudobinary group-III nitride semiconductors. © 2002 American Institute of Physics.

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