Isothermal and two-temperature zone selenization of Mo layers

Abstract

Glass/Mo, Mo foil, glass/Mo/In, and glass/Mo/Cu stacked layers were selenized in closed vacuum tubes by isothermal and/or two-temperature zone annealing in Se vapors. The selenization process was studied dependent on Se vapor pressure, temperature and time. Samples were selenized from 375 to 580°C for 30 and 60 minutes. The applied Se pressure was varied between 130 and 4.4̇103 Pa. The increase of MoSe2 film thickness was found to depend on the origin of Mo. MoSe2 thickness d L on Mo-foil was much higher than on sputtered Mo layers, and it depended linearly on time and as a power function dL∼PSe1/2 on Se vapor pressure. The residual oxygen content in the formed MoSe2 layers was much lower in the two-zone selenization process. If Mo was covered with Cu or In before selenization, these were found to diffuse into formed MoSe2 layer. All the MoSe2 layers showed p-type conductivity. © 2012 L. Kaupmees et al.