Hole-diffusion length and transport parameters of thin CdS films from a Schottky barrier

Abstract

The optoelectronic and transport properties of thin sprayed CdS films, having a thickness of less than 2 μm are reported. The use of two independent technics, surface photovoltage and photoelectrochemical measurements, led to a good agreement in the hole-diffusion length values. These range from 0.017 to 0.15 μm and behaved differently in two zones. A rapid increase of this parameter is observed below a film thickness of 0.4 μm. Above this thickness, the value obtained is constant. Specific space-charge widths are expected because of the respective measurement conditions. The hole-diffusion length decreases as carrier density increases. The hole lifetime shows a regular decrease as the thickness factor increases, while the hole-diffusion coefficient and mobility patterns are similar to that of the photocurrent.

Semiconductor-based photocatalysts and photoelectrochemical cells for solar fuel generation: a review

“…62) but a long charge carrier diffusion length up to the micrometer scale. [63][64][65][66] CdS has a band gap of 2.4 eV with the conduction band and the valence band that straddle the redox potentials for water splitting. 10,67 Thus, CdS is theoretically suitable for the overall water splitting under visible light irradiation.…”