| SM ISO690:2012|
FEDOROV, Vladimir; SUMAN, Victor; GAGARA, Ludmila; GASHIN, P.. Structure of CdTe-CdO-CdS-ito solar cells grown on glass substrates. In: Materials Science and Condensed Matter Physics. Editia a 8-a, 12-16 septembrie 2016, Chişinău. Chişinău: Institutul de Fizică Aplicată, 2016, p. 279. ISBN 978-9975-9787-1-2.
|Materials Science and Condensed Matter Physics
Editia a 8-a, 2016
Conferința "International Conference on Materials Science and Condensed Matter Physics" |
8-th Edition, Chişinău, Moldova, 12-16 septembrie 2016
Solar cells based on polycrystalline CdS-CdTe heterojunction still remain one of the most promising candidates for large-scale applications in the field of photovoltaic energy conversion due to unrealized full potential. Reported efficiency of these cells1 is about 16-17% that far from theoretically predicted2 28-30%. The main cause of efficiency loss is due to recombination losses. The problems can be solved by the reducing of the pin-hole density and intergrain cavities at the CdS-CdTe interface. The efficiency of CdS-CdTe heterojunction performance can be improved3 by the intentional forming on CdS surface CdO nanocrystals during annealing in oxygen atmosphere. CdO nanocrystals reduce shunt resistance and do not increase the optical losses in multilayered structure. Our approach is a controllable deposition of 2-10 nm CdO layers on CdS surface before forming of CdS-CdTe heterojunction. We use a hybrid technique for preparation of multilayered structures: the Indium-Tin-Oxide and CdO layers were prepared by sputtering of in oxygen atmosphere, and semiconducting CdTe and CdS were deposited by close spaced sublimation (CSS) technique. The crystal parameters of grown structure were examined by X-ray diffraction (XRD). The presence of CdO layer affects the nucleation process, increasing the texturing in CdTe layer with preferred orientations (100) and (220). The layers surface morphology was characterized by atomic force microscopy (AFM). Analysis of morphology of CdS layers shows that lateral grain sizes varied in the range of 140-390 nm with roughness around 20-30 nm (Fig.1a). Grain sizes of CdTe (Fig.1b) are located in the range 1.1-1.3 µm at roughness 270-310 nm. The morphology of semiconducting layers is strongly depended from growth conditions of CSS. The introducing of the CdO sublayer has little effect on the size of the grain, partly changing the preferable orientation of the succeeding CdTe layer.