On some parameters determining the efficiency of Schottky solar cells based CdS

A series of models given for CdS/Cu/sub 2/S cells show that the photocurrent is generated in Cu/sub 2/S and the open-circuit voltage V /SUB oe/, is controlled by the properties of CdS Iayer. The control of the diode characteristics is made by the CdS intrinsec layer adjoining the Cu/sub 2/S layer, the tunnelling effect through this layer, the recombination rate and the interface field. The barrier height in CdS is given by the interface state density and the space charge, that restrict the current through CdS. Hence, we can see that the prevailing role is played by CdS. In this work, we want to realize a CdS Schottky type diode and to determine the activation energy, the barrier height and the state density at metal-semiconductor interface. Too the work presents a simple method to determine the diffusion length of the minority carriers in Schottky diode, Al-CdS. The values of parameters estimated one can draw the conclusion that in order to increase the conversion efficiency of this structure the optimization of the production technology is necessary, aiming at the decrease of the dark current and the increase of the barrier height.