AVS 52nd International Symposium
    Thin Films Monday Sessions
       Session TF-MoP

Paper TF-MoP38
Optical and Charge Transport Properties of p-type (CdTe)@sub x@Cu@sub y@O@sub z@ Films: a Novel Material for Photovoltaics and other Optoelectronic Applications

Monday, October 31, 2005, 5:00 pm, Room Exhibit Hall C&D

Session: Aspects of Thin Films Poster Session
Presenter: S. Jiménez-Sandoval, Cinvestav-IPN, Mexico
Authors: S. Jiménez-Sandoval, Cinvestav-IPN, Mexico
J. Carmona-Rodríguez, Benemérita Univerisidad Autónoma de Puebla, Mexico
O. Jiménez-Sandoval, Cinvestav-IPN, Mexico
R. Lozada-Morales, Benemérita Universidad Autónoma de Puebla, Mexico
M. Meléndez-Lira, Cinvestav-IPN, Mexico
C.I. Zúniga-Romero, Cinvestav-IPN, Mexico
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Cadmium Telluride is a technologically important semiconductor material for optoelectronic applications; more specifically, for photovoltaic applications and infrared detection. The search for CdTe-based materials that may improve some of the still difficult matters regarding CdTe-based technology is currently underway. This work reports the continuation of our previous work on Cu@sub x@Cd@sub 1-x@Te@footnote 1@ and on Cd-Cu-Te-O systems@footnote 2@ by presenting the structural, optical and electrical properties of (CdTe)@sub x@Cu@sub y@O@sub z@ films grown by reactive rf-magnetron co-sputtering; it is shown that the optical and charge transport properties may be tailored by changing the relative concentration of the four elements. The films were obtained by co-deposition from CdTe and Cu targets under a controlled oxygen flow rate of 11 sccm. The power applied to the Cu target was 0, 10, 20, 30, 40, and 50 W, for different runs. The X-ray diffraction patterns indicated that the films are a mixture of CdTe-type cubic/hexagonal phases; however, it was observed that the hexagonal phase was favored for higher copper concentrations. The chemical composition was analyzed by energy dispersive spectroscopy. The results indicated that the atomic concentration of Cd and Te has nearly identical values in all samples, and decreases as the copper concentration increases from zero to 25 at.%. For films grown with 40 and 50 W in the copper target x=y=z=0.25. The bandgap varied from 1.62 eV (no Cu) to 1.48 eV (25 at.% Cu ), a value quite appropriate for the absorbing layer in a solar cell. The four probe method was useful to determine the p-type resistivity of the films grown with Cu powers of 20 W and above. The values obtained ranged from 1.6 x10@super 3@ to 6.5x10@super -3@ ohm-cm. @FootnoteText@ @footnote 1@ S. Jiménez-Sandoval, S. López-López, B.S. Chao, M. Meléndez-Lira, Thin Solid Films 342 (1999)1.@footnote 2@ S. Jiménez-Sandoval et al., To be published (2005).