Novel CdSe Solar Cell

CdSe is potentially an important material for making tandem cells with Si. Previously, we have shown good performance in a hybrid p-i-n device, where the p layer was an organic semiconductor (P3HT or PEDOT:PSS) and the n layer was n-CdS. Here, we report on a novel, all-inorganic CdSe solar cell which uses a combination of a very thin a-(Si,C):H intrinsic and p layers along with a thick CdSe layer to make a p-i-n device. This new structure is an all inorganic solar cell and it eliminates the problems of shorts in the CdSe layer by using the thin a-(Si,C):H layer to seal up the shorts during growth. We have obtained both a reasonable current (~8 mA/cm
²
) and a high voltage (>0.75V) in this inorganic device. The quantum efficiency data clearly shows collection from both the very thin a-(Si,C):H layer and the underlying CdSe layer. The QE data also shows that there are no spikes at the interface between CdSe and CdS for electron transport, and no spikes for hole transport between CdSe and a-(Si,C):H. We also report on the influence of CdCl2 annealing conditions and heat treatment on device performance and fundamental material properties and show that too high a temperature during annealing can damage the material.