The behavior of the surface charge density in HgxCd1−xTe epilayers due to hydrogenation and annealing

Electrolyte electroreflectance (EER), Fourier transform infrared (FTIR) transmission, and Hall effect measurements have been carried out to investigate the behavior of the surface charge density in hydrogenated and annealed HgxCd1−xTe epilayers grown on nominally undoped p-CdTe (211) B-orientation substrates by molecular beam epitaxy. The transition energy and the broadening parameter were obtained from the fitting in the third-derivative functional form of the EER spectra. The results of the EER measurements showed the decrease in the surface charge density as a result of the passivation of the internal impurities after hydrogenation. The EER results after hydrogenation and after annealing showed an increase in the surface electric field resulting from a decrease in the number of acceptors. The behavior of the surface charge density in hydrogenated and annealed HgxCd1−xTe epilayers obtained from the EER measurements is in good agreement with that measured from the Hall effect measurements.