In-plane and growth direction electron cyclotron effective mass in short period InAs/GaSb semiconductor superlattices

Abstract

In plane and growth direction electron effective mass in short period InAs/GaSb semiconductor superlattices (SL) was measured using cyclotron resonance at different orientations of magnetic field with respect to SL growth direction. It was demonstrated that the electron spectrum near the bottom of the SL subband has 3D character, with the in-plane effective masses ranging from 0.023 m0 to 0.028 m0 and growth direction effective masses of 0.03–0.034 m0 depending on the SL period and growth conditions. The measured effective masses are close to those calculated in the weak coupling limit of the Kronig-Penney model. In this limit the SL electron effective mass is a weighted average of the electron effective masses of corresponding bulk materials. Correlation between the magnitude of cyclotron mobility, amplitude of negative magnetoresistance, and steepness of the long wavelength side of the photoluminescence spectrum indicate that the crystalline structure disorder is a major factor contributing to the momentum relaxation time of the electrons.