The present invention describes a method of producing a p-type light-absorbing semiconductor copper zinc tin selenide/sulfide (Cu2(ZnxSn2-x)(SySe1-y)4) (abbreviated CZTS) with electrochemical deposition. It can be used in the production of solar cell when combined with an n-type inorganic or an organic semiconductor layer. The present method comprises a one-step or a sequence of depositions using electroplating to fabricate a low-cost and large-area CZTS solar cell, without using expensive and complicated deposition techniques or highly toxic and flammable chemicals in the production process. The present method significantly reduces the cost and energy requirement for production of solar cell.