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This work reports the crystallization, microstructure, and surface composition of Cu In0.7 Ga0.3 Se2 ( CIGS) thin films grown by femtosecond pulsed laser deposition at different annealing temperatures. The structural and optical properties of the CIGS films were characterized by X-ray diffraction, Raman scattering, UV-visible spectroscopy, and Hall effect measurement. The results indicate that binary crystals of CuSe initially formed on the as-deposited film, but then completely turned into a quaternary chalcopyrite structure after annealing at 400°C. Phase transformation significantly affects the surface morphology, Hall properties, and band gap. Transmission electron microscopy further revealed that an interface between the Mo substrate and CIGS crystallites contains an amorphous layer even at the high temperature of 500°C. For the application of photovoltaic devices, we also report on the photoresponse of both as-deposited and annealed films as demonstrated by preliminary tests. [ABSTRACT FROM AUTHOR]

CuGaS2nanorods were synthesized by irradiating the precursor solution with intense X-rays. The products are single crystal nanorods with preferential [220] growth and a uniform size distribution. We also report on the photoresponse of drop-cast films of these nanorods. [ABSTRACT FROM AUTHOR]

Abstract: The films of doped chalcopyrite semiconductor, i.e. CuIn1−x M x Se2 (M=Cr, V and Ti), were grown on the soda lime glass substrates by pulsed laser deposition (PLD). The deposition was carried out with a single sintered target, which contained all the elements. X-ray diffraction of the films deposited at room temperature (RT) showed only the reflection lines from the chalcopyrite phase. However, Raman spectroscopy revealed two extra weak peaks, which might be identified with the secondary phase CuSe or a segregation of another chalcopyrite phase with different compositions. The film crystallinity and the homogeneity of composition were improved by the post-deposition annealing at 400°C, after which the grain size was increased from 3nm to 19nm and the above two weak Raman peaks disappeared. Hall-effect measurements indicated that all the films were p-type semiconductors and the doped films had lower carrier concentration but higher mobility. Optical absorption measurements showed that the bandgap of doped films was increased, varying from 1.06eV in undoped CuInSe2 to around 1.20–1.36eV in CuIn1−x M x Se2. Compared to the well-known CuIn1−x Ga x Se2 (i.e. Ga doping), the dopants studied in this work were much more effective to increase the bandgap of CuInSe2. [Copyright &y& Elsevier]

We demonstrate a single-step X-ray irradiation process that yields high-quality Cu(In1-xGax)S2 nanocrystals in colloidal solutions, with complete control of size and composition. Thin films produced by drop-casting exhibit high-quality photoresponse, confirming that our process is suitable for microelectronics applications.