In situ reflectance difference spectroscopy: nitrogen-plasma doping of MBEgrown ZnTe layers

We performed in situ reflectance difference spectroscopy (RDS) during Nitro gen-doping of ZnTe thin films grown by molecular beam epitaxy (MBE): to the MBE chamber, equipped with an electron cyclotron resonance cell for N-plas ma generation, an RDS system is attached via a strainfree mounted normal in cidence viewport. At first, ZnTe (0 0 1)-surfaces have been studied under v arying exposure conditions, like Zn, Te and/or N-plasma flux onto the sampl e surface. Furthermore, RDS features in the vicinity of the E-1 and E-1 + D elta(1) transitions were used to optimize online the doping performance of the N-plasma cell by varying the sourer parameters, like N-pressure and inp ut power. In addition, ex situ BE spectra of doped layers with different ca rrier concentrations have been investigated. (C) 1999 Elsevier Science B.V. All rights reserved.