Structure and Optoelectronics of Electrodeposited Cadmium Ditelluride (CdTe(2))
2008 (English)In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 20, no 20, 6550-6555 p.Article in journal (Refereed) Published
Electrodeposition is a powerful method to perform low cost, large area CdTe deposition. Good quality semiconductor materials for photovoltaic applications as well as high growth rates have been achieved using this technique. Electrodeposition in acidic solution is considered in this work. In these conditions, depending on the applied potential, a transition from the crystalline CdTe compound to a quasi-amorphous CdTe, compound has been shown. The present work explores the properties of this new compound and compares them to those of the classical electrodeposited CdTe. The experimental study (X-ray diffraction (XRD), optical transmission, and ellipsometry measurements) is complemented by theoretical results obtained by first principles modeling using density functional theory. The pyrite structure, with a lattice parameter a = 7.250 angstrom and an internal parameter u = 0.389, is found as the theoretically favored crystal structure. The corresponding calculated X-ray diffraction diagram is comparable to those experimentally obtained. Considering both experimental and modeling results the band-ap should be indirect with a value (1.08 eV) lower than that of electrodeposited CdTe. Moreover, this Te-rich compound is shown to be highly absorbent in the 1.5-4 eV energy range. This property can be partially explained by the flat band structure profile obtained by ab initio calculations. Finally, XRD under heating carried out on CdTe(2) shows that this compound is decomposed into CdTe + Te at relatively low temperature (> 150 degrees C).
Place, publisher, year, edition, pages
2008. Vol. 20, no 20, 6550-6555 p.
IdentifiersURN: urn:nbn:se:kth:diva-62840DOI: 10.1021/cm801887vISI: 000260254400040OAI: oai:DiVA.org:kth-62840DiVA: diva2:481228
QC 201201262012-01-202012-01-202012-01-26Bibliographically approved