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 transitio n energy and the broadening parameter were obtained from the fitting i n the third-derivative functional form of the EER spectra. The results of the EER measurements showed the decrease in the surface charge den sity as a result of the passivation of the internal impurities after h ydrogenation. The EER results after hydrogenation and after annealing showed an increase in the surface electric field resulting from a decr ease in the number of accepters. The behavior of the surface charge de nsity in hydrogenated and annealed HgxCd1-xTe epilayers obtained from the EER measurements is in good agreement with that measured from the Hall effect measurements.