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

摘要

We performed in situ reflectance difference spectroscopy (RDS) during Nitrogen-doping of ZnTe thin films grown by molecular beam epitaxy (MBE): to the MBE chamber, equipped with an electron cyclotron resonance cell for N-plasma generation, and RDS system is attached via a strainfree mounted normal incidence viewport. At first, ZnTe (0 0 1)-sufaces have been studied under varying exposure conditons, like Zn, Te and/or N-plasma flux onto the sample srface. Furthermore, RDS features in teh vicinity of the E_1＋Δ_1 transitions were used to optimize online the doping performance of the N-plasma cell by varying the source parameters, like N-pressure and input power. In addition, ex situ RD spectra of doped layers with different carrier concentrations have been investigated.