Excitons deep in the intrinsic absorption region of TlGaSe2 single crystals
Abutalybov G. I., Salaev E. Yu.
A new absorption line has been discovered deep in the intrinsic absorption region, at EB = 2.3804 eV, at Τ — 1.8 К. This line is shown to be due to the formation of direct free excitons at point Г at the center of the Brillouin zone. The sharp change in the absorption coefficient atT= 105 K, accompanied by a vanishing of exciton absorption peak B, is attributed to structural phase transitions in the TlGaSe2 single crystals.