Self-assembled quantum dot formation during the growth of In 0.4Ga 0.6As on GaAs(0 0 1) by metal-organic vapor phase epitaxy: The role of In segregation

Abstract

The stabilization of planar In 0.4Ga 0.6As on GaAs, above thickness typically reported to undergo spontaneous island formation, has been observed. The effect of growth temperature, AsH 3 partial pressure, and In 0.4Ga 0.6As thickness on island size and density was evaluated. Planar films are stabilized by low growth temperatures and high AsH 3 partial pressures. Spontaneous island formation is enhanced by high growth temperatures and low AsH 3 partial pressures. The results presented are interpreted within the phenomenology of In segregation to the surface, which has been identified previously for the InGaAs/GaAs system. Based on equilibrium models for the critical thickness for island formation, the critical segregation layer thickness for island formation is predicted to be 0.6 nm.