Journal of Crystal Growth, Vol.224, No.1-2, 32-40, 2001
Photoluminescence studies of ZnSe starting materials and vapor grown bulk crystals
Low-temperature photoluminescence (PL) spectra were measured on ZnSe starting materials provided by various vendors and on bulk crystals grown from these starting materials by physical vapor transport (PVT) to study the effects of purification and contamination during PVT process. The impurity levels in one set of starting material/grown crystal were also measured by grow discharge mass spectroscopy (GDMS). The purification effect of pre-growth heat treatments and the PVT process is evidenced from the GDMS results which showed orders of magnitude reduction in the Li and Na concentration and a factor of 3 reduction in the O content after growth. The PL spectra showed that the strong emissions associated with Li (or Na) In one of the starting materials disappeared after growth. The GDMS results also showed increases in the Al and Si contents by orders of magnitude after growth. To evaluate the contamination of the crystal during the high temperature,growth process, three growth runs were processed using similar growth parameters but different furnace environments, The PL spectra suggest that the Al contamination originated from the fused silica ampoule and that the Inconel cartridge might have been the cause of the broad Cu green and Cu red bands observed in one of the grown crystals. Published by Elsevier Science B.V.