Published online by Cambridge University Press: 12 May 2015
Two alternative chemical etchings (aqueous solution of bromine and bromine methanol solution) have been here tested to replace the KCN etching step in Cu-rich CuInSe2 based solar cells fabrication process. This new oxidative etch aims also at smoothing and thinning the as-grown films. This directly affects the interface between the absorber and the CdS buffer, interface which causes problems for Cu-rich solar cells. We present here the effect of these two alternative etchings on both the absorber surface and the solar cells parameters: whereas the bromine methanol etching destroys the solar cell, the aqueous solution of bromine leads to an improvement of the device through reduced interface and tunneling enhanced recombination.