Modification of dead layer on surfaces of CuInSe₂ and its alloys

The efficiency of CuInSe₂ or its alloy films, synthesized with selenization techniques, is often limited by the presence of a defective surface region, equivalent to a `dead layer'. Its presence is manifested by photocurrent losses in the short wavelength range. This paper explores some chemical and electrochemical surface treatments to eliminate or minimize the dead layer effect, using photocurrent spectral response to monitor the surface quality. Specific chemical treatments dramatically enhance the short wavelength response and device performance. Electrochemical treatments also improve the quantitative spectral output. But prolonged cathodic polarization has a deleterious effect on the quantum efficiency. Implications of the results to the performance of PV devices are discussed.