Hydrostatic pressure dependence of the exponential optical absorption in CdInGaS4

The optical‐absorption spectra in the semiconductor CdInGaS4 have been measured precisely at various hydrostatic pressures up to 20 kbar, and analyzed in the region below the fundamental absorption edges. It can be seen that the absorption coefficients plotted semilogarithmically vary linearly with photon energy below the fundamental absorption edges at each hydrostatic pressure. The steepness of the absorption edge is proportional to the inverse of hydrostatic pressure.