Thin films of CdTe/CdS grown by MOCVD for photovoltaics

A doped CdTe/CdS photovoltaic structure has been grown onto ITO coated glass substrates by metal organic chemical vapour deposition (MOCVD). CdS is nucleated from dimethylcadmium and ditertiarybutylsulphide at 290 degrees C followed by CdTe growth from DMCd and diisopropyltelluride at 300-310 degrees C, The grain size of the CdTe is approximately the same as the underlying CdS layer and with a strongly prefered (1 1 1) orientation. This has been achieved without post growth annealing or chemical treatment. Similarly, doping of both the CdS and CdTe layer have been achieved during growth to form a n-p junction. The dopant precursors are n-butylchloride for the CdS layer and dimethylaminoarsenic for the CdTe layer. Preliminary photovoltaic devices show good rectification, with an open circuit voltage of 0.14 V, and fill factors of 35-50%. (C) 1998 Elsevier Science B.V. All rights reserved.