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 and4.4⋅103 Pa. The increase of MoSe2film thickness was found to depend on the origin of Mo. MoSe2thicknessdLon Mo-foil was much higher than on sputtered Mo layers, and it depended linearly on time and as a power functiondL~PSe1/2on Se vapor pressure. The residual oxygen content in the formed MoSe2layers 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 MoSe2layer. All the MoSe2layers showedp-type conductivity.

Study of structural and optical properties of kesterite Cu2ZnGeX4 (X = S, Se) thin films synthesized by chemical spray pyrolysis

“…As for concern of possible secondary phases in CZGSe film, it is reported that secondary phases, Cu 2 Se or CuSe 2 , has Raman peaks at 270 cm −136 and peaks at 147 and 260 cm −1 are assigned to CuSe. 37,38 MoSe 2 can be identified by Raman peaks at 169, 240, 280 and 350 cm −139, 40 and ZnSe phase can be at 210 and 254 cm −1 . 41 Herein, we just observed Cu 2 Se or CuSe 2 secondary phase in Raman spectra of CZGSe thin films.…”

A Universal and Facile Method of Tailoring the Thickness of Mo(Sx,Se1−x)2, Contributing to Highly Efficient Flexible Cu2ZnSn(S,Se)4 Solar Cells

“…On the one hand, controlling the annealing temperature and time are the common routes to obtaining high‐quality absorbers and reducing the formation of Mo(S x ,Se 1− x ) 2 . [ 18,27 ] Although decreases in annealing time and temperature could reduce the formation of Mo(S x ,Se 1− x ) 2 effectively, it would also lower the crystalline quality of the absorber. [ 28 ] On the other hand, the insertion of a barrier layer on top of Mo is widely adopted to modify the back contact.…”

On the kinetics of MoSe2 interfacial layer formation in chalcogen-based thin film solar cells with a molybdenum back contact

“…A similar study, where Mo films were selenized to form MoSe 2 , has been reported in the literature. 12 In this study, the activation energy of MoSe 2 growth was determined 0.7 6 0.1 eV by fitting a MoSe 2 thickness vs. temperature (1/T) with a single exponent over the entire annealing temperature range used (375-580 C), implicitly assuming a priori that a limiting case-where one kinetic process is much slower than the others connected in series-was in play. Our finding that the process is diffusion-limited now supports their assumption and indeed their estimated activation energy of 0.7 6 0.1 eV is very close to our estimation of E D2 .…”