Luminescence study of donors and acceptors in CdGeAs2

Abstract A photoluminescence (PL) study has been performed on a set of p-type bulk single crystalline samples of CdGeAs2. At liquid-helium temperatures, a PL band peaking near 0.55 eV was observed in samples with enhanced absorption at 5.5 μm. This PL band was observed to vary as much as 40 meV in peak position in our sample set. The PL peak position depends on the net acceptor concentration (i.e., hole concentration) and the PL peak shifts to higher energy as the excitation intensity increases. We show that this behavior is well explained by the model of donor–acceptor pair (DAP) recombination in the presence of potential fluctuations.