Thin films of CdTe/CdS grown by MOCVD for photovoltaics

A doped CdTe/CdS photovoltaic structure has been grown onto ITO coated glas s substrates by metal organic chemical vapour deposition (MOCVD). CdS is nu cleated from dimethylcadmium and ditertiarybutylsulphide at 290 degrees C f ollowed by CdTe growth from DMCd and diisopropyltelluride at 300-310 degree s 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, do ping of both the CdS and CdTe layer have been achieved during growth to for m a n-p junction. The dopant precursors are n-butylchloride for the CdS lay er and dimethylaminoarsenic for the CdTe layer. Preliminary photovoltaic de vices 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.