Electron and hole effective masses for two-dimensional transport in strained-layer superlattices

The first theoretical study of the electron and hole effective masses along the layers of (100) strained-layer superlattices grown from direct and indirect gap materials is presented. The results indicate that the large layer strains in these structures can produce electron masses associated with the X valleys and hole masses which are significantly reduced from bulk values. The electron values are typically ～ 0.2 m_e and the hole values are typically <0.1 m_e. These results have important implications for the low field transport properties of strained-layer systems.