Papers by Author: Rachmat Adhi Wibowo

Abstract: Cu(In0.75Al0.25)Se2 thin films were prepared using both one-step sputtering and two-stage process involving sputtering and selenization. Structure and properties of the films were analyzed and compared between the methods. All films had good adhesion to the substrate and showed strong (112), (220)/(204) peaks while minor secondary phase CuxSe was observed in the films from selenization. This paper compares the visibility of one step sputtering process and selenization of sputtered binary selenides layers to produce Cu(InAl)Se2 thin films (CIAS) for solar cell absorber applications. One step sputtering deposition from binary selenides powder compacted targets can produces CIAS films with better structural and optical properties compared to films produced by selenization of sputtered precursors.

Abstract: Al-doped ZnO (AZO) thin films were grown on Corning 1737 glass by RF Magnetron Sputtering under premixed hydrogen-argon (H2/Ar) sputtering gas. It is found that the introduction of various H2 concentrations during sputtering deposition altered the properties of Al-doped ZnO films. The presence of H2 during AZO growth at low deposition temperature leads to the growth of a-axis preferential orientation crystal whereas c-axis preferential orientation occurred only at higher deposition temperature. Highly oriented c-axis (002) crystal has been successfully grown under 3% H2 concentration at 200°C deposition temperature. Film’s resistivity is appeared to be a function of H2 concentration. Additional H2 concentration in sputtering gas increased of film’s transmittance up to 85% at visible-near infra red spectra while it caused the Burstein-Moss shift toward the blue region at 350 nm wavelength.

Abstract: Cu2ZnSnSe4 (CZTSe) thin films were grown on Corning glass 1737 by sequential methods of sputtering deposition and selenization process. As-grown films showed that elemental Cu, Zn, and Sn were in the nearly CZTSe stoichiometric ratio with Se-deficiency as detected by Energy Dispersive X-Ray spectrometry (EDX). In order to attain film stoichiometry, as-deposited films were subjected to selenization process in tube furnace under Ar ambient at different selenization temperatures for 10-60 min. It was found that compositions of binary compound in the sputtering target as well as selenization are critical for the growth of the CZTSe films. The structural characteristics of the selenized CZTSe films revealed a highly oriented stannite CZTSe phase with (112), (220/204) and (312/116) growth orientations and a CuSe secondary phase. By using 0.5% KCN solution, CuSe secondary phase could be totally etched from the CZTSe film surface.

Abstract: Cu(In1-xAlx)Se2 films were prepared using a two-stage process of sputtering and selenization. Stacked elemental layer precursors of Cu, In and Al were deposited onto corning glass substrates by RF magnetron sputtering. Precursors with different Cu/(In+Al) and In/Al ratio were selenized using elemental Se-vapor at atmospheric pressure in a commercial tube furnace under constant argon gas flow. Films with good adhesion to the substrate were grown successfully. All of the films show strong (112) and (220)/(204) CIS peaks. Addition of Al, at expense of In, shifts the peaks towards higher 2θ. This paper explores the possibility to use sputtering deposition and selenization process to grow Cu(InAl)Se2 thin films for solar cells applications.