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Zincblende-to-diamond-lattice structural phase transitions should occur in metastable (III–V)1−xIV2x alloys at a transition composition xc that is controllable by growth conditions. The effect of this transition should be visible both in the electronic as well as the vibrational properties of these alloys. For example, in the prototypical (III–V)1−xIV2x alloy, (GaAs)1−xGe2x, the observed anomalous V-shaped bowing of the direct gap is explained in terms of the phase transition, which occurs at the minimum of the “V.” Predictions are made for the band gaps of new metastable alloys, such as (GaSb)1−xSn2x. Consequences of this transition for (III–V)-IV superlattices are also discussed.

The energy band structure of wurtzite-structure semiconductive InN is predicted using empirical nearest-neighbor tight-binding theory. The tight-binding parameters are extrapolated from those of zincblende InP, InAs, and InSb by using empirical rules for the dependences of the parameters on bond length and on row of the Periodic Table. The predicted band gap is direct and agrees well with the data for this potential orange light-emitter. It is suggested that zincblende InN, if it can be grown, also will have a band-gap near 2 eV.