Mobility and Phonon Scattering in Epitaxial PbSe Films

Non-intentionally doped Pbse crystalline films are grown on insulating BaF2(111) by molecular beam epitaxy.The measurements of Hall effect and temperature-dependent resistivity show P.type conductivity of the PbSe epitaxial films.At 295K all of the samples display hole concentrations of (5～8)x 10^17cm3 with mobilities of about 300cm2/(V·s). The hole mobility increases with the decrease of temperature and at 77K hole mobility is as high as 3 x 10^3 cm2/(V·s). Carrier scattering mechanisms limiting hole mobilities are theoretically analyzed，and the calculation shows that in the temperatures between 77～295K, the scattering of polar optical modes dominates the impact on the observed hole mobilities in PbSe epitaxial films.Raman spectra measurements at T≥200K observed strong optical phonon scatterings in the PbSe epitaxial films, which is consistent with the hole mobility measurements.