Layers For Solar Cell Applications Research Articles

CdS Thin Films Prepared by RF Magnetron Sputtering in Ar Atmosphere

CdS thin films were prepared using rf planar magnetron sputtering in Ar atmosphere. Different deposition temperatures between 150 and 250°C and different rf powers between 30 and 130 W were used. The films had hexagonal structure with crystallites oriented in the (100) direction. The increase of deposition temperature caused an increase in the crystallite size (from 380 to 450 A) and a decrease in the resistivity (from 3.87 to 0.95 Q cm). The increase in the rf power (from 30 to 130W) caused a decrease in the grain size (from 480 to 320 A) and an increase in the resistivity (from 0.51 to 2.05 Q cm) above 70 W. The average optical transmission in the visible region of the spectrum ranged between 71 and 86%. The quality of the films as window layers for solar cell applications was investigated.

Investigation of the influence of the electrodeposition potential on the optical, photoelectrochemical and structural properties of as-deposited CdTe

Abstract The electrodeposition of cadmium telluride on cadmium sulphide deposited from a chemical bath is investigated with the aim of improving the structural and optical properties of the CdTe layers for solar cell applications. The CdTe layers are characterized by X-ray diffraction spectroscopy, optical transmission measurements and photoelectrochemical measurements. The influence of the electrodeposition potential on the conductivity type of the deposited CdTe is demonstrated. Spectral response measurements are used as an analytical method to study the optoelectronic properties of CdTe. Thickness-dependent spectral responses reflect a change of doping type for electrodeposition potentials more positive than +5 mV vs. the deposition potential of elemental cadmium. A front- and back-side illumination technique is used to determine the position of the active junction which varies between a n-CdS/p-CdTe and a n-CdTe|electrolyte junction. The width of the space charge layers and the doping concentrations are determined by using the Gartner equation for fitting the quantum efficiency vs. absorption coefficient plots.