Photoluminescence of undoped and neutron-transmutation-doped InSe

Photoluminescence (PL) spectra of undoped and neutron-transmutation-doped I nSe samples at 15 K are reported. The undoped InSe PL spectrum clearly show s the free exciton line and an exciton-neutral acceptor complex recombinati on. A structure of partially resolved transitions is observed between 1.315 and 1.330 eV, whose nature is discussed. An exciton bound to the native do nor of E-D=19 meV is also reported. Neutron-transmutation doping attenuates the excitonic transitions and increases the intensity of lower energy band s. This behavior is interpreted in terms of defects remaining after the ann ealing. A native acceptor level 40 meV above the valence band and two donor -acceptor pair transitions are identified. (C) 2000 American Institute of P hysics. [S0021-8979(00)05220-8].