Growth and p-type doping processes in MOVPE of ZnSe have been studied by optical probing methods called RD (reflectance difference) and SPI (surface photo-interference). As for the dopant source, tertiarybutyl-amine (tBNH2) was extensively used in this work, because it is one of the most useful dopant sources in photo-assisted MOVPE of widegap II-VI compounds. Oscillations with monolayer periodicity in RD signal traces have been successfully detected for the first time using a He-Ne laser beam in MOVPE of ZnSe. One of the most important findings is that tBNH2 molecules are selectively adsorbed on the "Zn-terminated" surface and not on the "Se-terminated" surface; this suggests that selective doping during Zn-source (DMZn) supply and/or on Zn-terminated surfaces will be effective for improving the doping efficiency.
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