In situ reflectance difference spectroscopy of N-plasma doped ZnTe grown by molecular beam epitaxy

In situ reflectance difference spectroscopy (RDS) has been performed during growth and nitrogen-doping of ZnTe thin films fabricated by molecular beam epitaxy. The doping level of the ZnTe samples can be determined by evaluat ing the RD spectra in the vicinity of the E-1 and E-1 + Delta(1) transition s. RDS features in this spectral range were used to optimize online the dop ing performance of the N-plasma cell. Furthermore, doping-induced surface p rocesses have been investigated, like surface saturation with activated N s pecies and surface Fermi level pinning occurring at ambient pressure. (C) 1 998 American Institute of Physics. [S0003-6951(98)00952-8].