TEMPERATURE-DEPENDENCE OF BAND-GAPS IN HGCDTE AND OTHER SEMICONDUCTORS

Band-edge shifts induced by the electron-phonon interaction are calcul ated for HgCdTe alloys and various semiconductor compounds starting fr om accurate zero-temperature band structures. The calculated temperatu re variation of gaps agrees with experiments to better than 10% in all materials except InAs and InSb where the deviation is about 50%. Whil e the simple picture that the intra (inter)-band transitions reduce (i ncrease) the gap still holds, we show that both the conduction band ed ge E(c) and valence band edge E(v) move down in energy. These shifts i n E(c) affect the valence band offsets in heterojunctions at finite te mperature. The temperature variations of valence band offset and the e lectron effective mass are also reported.