′�?, with a frequency of 295 cm−1, is attributed for the stretching vibration of Ga–Se bonds. The two-phonon absorption of the 295 cm−one phonon corresponds to the crystal IR absorption edge, instead of the residual absorption peak. Density functional principle computations display which the residual absorption in the BGSe crystal https://raymondhwitf.blue-blogs.com/39793962/how-much-you-need-to-expect-you-ll-pay-for-a-good-baga4se7-crystal