Photoluminescence study of p-type CdGeAs2 ordered semiconductor crystals

Results of a photoluminescence (PL) study as a function of excitation laser power, sample temperature, crystal orientation, and polarization are reported for the nonlinear optical material CdGeAs2. One broad weak PL peak near 0.38 eV, and another somewhat narrower and often far brighter PL peak near 0.55 eV were found at 4 K. The high energy PL peak shifts first towards lower, then higher, and back to lower energies again as the temperature increases from 2.2 to 295 K. This high energy peak is attributed to donor-acceptor pair dominant transitions at low temperatures, but it is attributed to band-to-band dominant transitions at higher temperatures. Strongly polarized PL was observed with the E field of the PL parallel to the material's c axis, and a polarization ratio as high as 6:1 was obtained. (C) 1997 American Institute of Physics.