RAMAN INVESTIGATION OF INSE DOPED WITH GAS

The Raman spectrum of InSe doped with GaS exhibits appreciable changes at low doping densities indicating considerable changes on introducin g GaS. The photoluminescence as well as resonance Raman study shows th at the exciton energy is shifted towards higher energy as a result of doping. At resonance, both the one- and two-phonon polar modes are obs erved, although considerably broadened. This indicates that the GaS-do ped InSe develops significant topological disorder. Resonance Raman st udy shows that increasing the dopant broadens the resonance but the ex citonic energy does not change as a result of the increase in the GaS in InSe. The scattering also exhibits considerable temperature depende nce, so that it is possible to temperature tune the resonance in the d oped samples at low temperatures.