CRITICAL LAYER THICKNESS OF IN0.80GA0.20AS IN0.52AL0.48AS HETEROSTRUCTURES/

The critical layer thickness of n0.52Al0.48As/strained-In0.8Ga0.2As/In 0.52Al0.48As grown on InP substrates was investigated by measuring the photoluminescence spectra. These pseudomorphic heterostructures grown by molecular beam epitaxy attained the highest mobility, 16,200 cm2/V .s, at room temperature. The photoluminescence emission intensity decr eased in the thickness range of 20 to 25 nm for the In0.8Ga0.2As layer . These results indicate that the critical layer thickness of this str ucture follows the energy balance model rather than the mechanical equ ilibrium model. In addition, this critical value is in good agreement with the results based on the electron mobility behavior.