The photoluminescence spectra of undoped single crystals of the layered semiconductor were measured, between 10K and room temperature, at wavelengths ranging from 635 to 750nm. Two wide bands, centered at 644 and 695nm, were observed at 10K. A detailed analysis of the spectra, obtained by varying the excitation intensity and temperature, resulted in identification of the levels involved.

Defect Luminescence in Undoped p-Type GaSe. A.Aydinli: Philosophical Magazine Letters, 2001, 81[12], 859-67