Photoelectrochemical study of the amorphous-WO3-semiconductor–electrolyte junction

Abstract

The photoelectrochemical behaviour of amorphous anodic films grown on tungsten has been studied. The wavelength of the incident light is shown to influence the photoresponse of the amorphous films. The experimental results are interpreted on the basis of the semiconducting properties of the film and by taking into account the various mechanisms of transport occurring in amorphous materials. At longer wavelengths a Poole–Frenkel mechanism of electrical conduction in the non-extended states of the amorphous semiconductor is invoked in explaining the transport of photoinjected carriers. At the shortest wavelengths a ‘free-carrier-like’ mechanism of transport of the photogenerated carriers is suggested. In each case a different electrode-potential dependence of the photocurrent is obtained experimentally.