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HL: Fachverband Halbleiterphysik

HL 5: Photovoltaic

HL 5.3: Talk

Monday, March 26, 2007, 11:30–11:45, H14

Growth and band gap characterizations of single crystals in the series ZrS₂ Se_2−x — •Mohamed Moustafa, Thorsten Zandt, Christoph Janowitz, and Recardo Manzke — Institut für Physik, Humboldt-Universität zu Berlin, Newtonstraße 15, 12489 Berlin

Single crystals of layered transition metal dichalcogenides with composition ZrS₂ Se_2−x, where x varies within the range 0-2, were grown by the chemical vapour transport technique using iodine as a transporting agent. Growth conditions are reported and the characterizations of the grown crystals were carried out with the help of LEED and EDX techniques. In addition, the absorption coefficient α was determined from transmission measurements at room temperature and approximate values of the band gaps were determined from the intercepts of the linear plots of the absorption coefficient on the energy axis [1]. The determined band gaps show good correspondence for the photovoltaic applications which is for a single junction cell about 1.45 eV and for two junctions about 1.1 eV and 1.8 eV. The observed exponential behaviour part in the absorption curve in the gap is also interpreted [2].

[1] P.A. Lee et al., J.Phys. Chem. Solids 30, 2719 (1969)

[2] F. Urbach, Phys. Rev. 92, 1324 (1953)