Pressure Dependence of Band Gaps and Deep Centers in Chalcopyrite Semiconductors

We present a review of the effect of high pressure on the electronic, optical and defect properties in chalcopyrite semiconductors with the formula I–III–VI2. We show that the linear pressure coefficients of the band gap in these materials are not constant. While the bulk moduli of this family of semiconductors are rather constant, the dependence of the band gap on volume exhibits systematic trends when the group III cations are varied. We also found that there are deep center emissions whose pressure coefficients are larger than those of the band gap. We propose that the origin of these deep emissions are deep acceptors and their pressure coefficients can be understood in terms of p–d hybridization in the valence bands.