Highly strained [formula omitted] quantum wells grown on GaP and on an [formula omitted] buffer layer by gas-source molecular beam epitaxy

Abstract

We report gas-source molecular beam epitaxial growth of highly strained In x Ga 1−x P GaP quantum wells on GaP and on an In x 2 Ga 1−x 2 P buffer layer. High-resolution X-ray diffraction and photoluminescence (PL) have been used to characterize the material quality. Satellite peaks up to ±2nd order are observed from a 50 period In x Ga 1−x P(50 A ̊ ) GaP(50 A ̊ ) multiple quantum well (MQW) grown on an In x 2 Ga 1−x 2 P buffer layer, whereas only the 1st-order satellite peak is observed for the same structure grown directly on GaP under the same growth condition, which indicates better-quality In x Ga 1−x P GaP MQWs can be achieved by using an In x 2 Ga 1−x 2 P buffer layer. Furthermore, an increase in the X-ray satellite peak intensity of the In x Ga 1−x P GaP MQWs grown on the In x 2 Ga 1−x 2 P buffer layer has been observed as the period of the MQW increases, suggesting no structural degradation and an increase of the critical layer thickness of the MQWs. PL measurements also show that an In x 2 Ga 1−x 2 P buffer layer is effective in improving the optical quality of the In x Ga 1−x P GaP MQWs .