The temperature dependence of band offsets for semiconductor heterojunctions in general and for the particular cases of AlAs-GaAs and HgTe-CdTe

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Abstract
The authors devise a simple theory for the temperature dependence of the valence and conduction band offsets in semiconductor heterojunctions using the thermodynamic point of view. The temperature dependencies of the offsets originate from the separate contributions of holes in the valence bands and of electrons in the conduction bands of the two semiconductors to the temperature dependence of their respective band gaps. They use the earlier determination of these contributions by Heine and Henry (1975), from isotope shifts of luminescent lines due to impurities. By considering this temperature dependence of the band offset they suggest an explanation for the discrepancy between the determinations of AlAs-GaAs valence band offset by Wolford et al. (1986), and by Batey and Wright (1986). Whereas for most pairs of semiconductors the bands move in the same direction with varying temperature, for the particular case of HgTe-CdTe they move in opposite directions. From this they predict a much greater than usual temperature dependence for the band offsets for HgTe-CdTe junctions and reconcile the major discrepancy between valence band offsets determined by Kowalczyk et al. (1986), and by Chow et al. (1988).