Influence of CdS growth process on structural and photovoltaic properties of CdTe/CdS solar cells

The morphology of CdS layers grown by chemical bath deposition (CBD) and hi gh vacuum evaporation (HVE) have been investigated. The grains of CBD-CdS a re more compact and smooth than those of HVE-CdS. The annealing and CdCl2 t reatment cause grain growth, which is stronger for the CdCl2 treated sample s. The grain-size of the as-deposited CdTe on CBD-CdS is about 5 times larg er than of those grown on HVE-CdS. The structural and electrical properties of CdTe/CdS solar cells are strongly dependent on the CdS. The grain size of CdCl2 treated CdTe layers are similar, irrespective of the transparent c onducting oxide substrate and CdS deposition method. The efficiency of sola r cells on thin CBD-CdS is low (about 5.6%) because of pin-holes and a larg e intermixing of CdTe-CdS. The cells on HVE-CdS yield a higher current dens ity despite thicker HVE-CdS as compared to CBD-CdS. The efficiency of solar cells on HVE-CdS is 12.3%. (C) 2001 Elsevier Science B.V. All rights reser ved.