Single step deposition method for nearly stoichiometric CuInSe2 thin films
Abstract This paper reports the production of high quality copper indium diselenide thin films using pulsed DC magnetron sputtering from a powder target. As-grown thin films consisted of pin-hole free, densely packed grains. X-ray diffraction showed that films were highly orientated in the (112) and/or (204)/(220) direction with no secondary phases present. The most surprising and exciting outcome of this study was that the as-grown films were of near stoichiometric composition, almost independent of the composition of the starting material. No additional steps or substrate heating were necessary to incorporate selenium and create single phase CuInSe2. Electrical properties obtained by hot point probe and four point probe gave values of low resistivity and showed that the films were all p-type. The physical and structural properties of these films were analyzed using X-ray diffraction, scanning electron microscopy and atomic force microscopy. Resistivity measurements were carried out using the four point probe and hot probe methods. The single step deposition process can cut down the cost of the complex multi step processes involved in the traditional vacuum based deposition techniques.
The Patented Project Design for Preparing CuInSe2 Film
The patent provides one method for preparing of CuInSe2 (CIS) photoelectric thin film used in solar cell. It belongs to the field of photoelectric film preparation technology. The patent includes the following steps. First clean glass substrate; Secondly dissolve CuCl2•2H2O, InCl3•4H2O, SeO2 by different solvents, then mix the solution and adjust the pH of solution to obtain homogeneous precursor solution; Thirdly drop the precursor solution to the glass substrate, spin coating and dry for precursor film. Then put the precursor film into sealed container which contains the hydrazine hydrate (N2H4•H2O), and keep the sample not in contact with hydrazine. Finally the sample is heated at some temperature, which makes it cool and dry naturally, CuInSe2 photovoltaic thin film is obtained. The method used in the patent does not require high temperature, high vacuum conditions and sophisticated equipment. So it has the advantages of low cost, high efficiency and simplicity. It is easy to control the composition and structure of the CuInSe2 photovoltaic thin film. And the CuInSe2 photovoltaic thin film is pure phase, continuous and uniform. So it is one feasible process to prepare high performance copper indium selenide thin film.
Electrical, optical and structural properties of binary phase free CuInSe2 thin films
Electrical, optical and structural properties of secondary phase free CuInSe2 thin films deposited on glass substrates are studied. The activation energy (EA) has been calculated for the films using the Arrhenius plot and the band gap energy (Eg) has been obtained from the optical transmission spectra. EA varied between 15 meV and 75 meV and Eg varied between 0.95 eV and 0.98 eV. Structural parameters a and c are calculated for the tetragonal phase. The mean grain size of the polycrystalline films is 0.1 µm.