AVS 50th International Symposium
    Thin Films Wednesday Sessions
       Session TF-WeP

Paper TF-WeP7
Structural and Electronic Properties of (CdTe)@sub x@(In@sub 2@Te@sub 3@)@sub 1-x@ Thin Films Grown by RF Co-Sputtering@footnote 1@

Wednesday, November 5, 2003, 11:00 am, Room Hall A-C

Session: Poster Session
Presenter: S. Jimenez-Sandoval, Cinvestav-IPN, Mexico
Authors: S. Jimenez-Sandoval, Cinvestav-IPN, Mexico
M. Melendez-Lira, Cinvestav-IPN, Mexico
M. Zapata-Torres, CICATA-IPN, Mexico
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The semiconductor CdTe and In@sub 2@Te@sub 3@ can be employed to form the ternary compound (CdTe)@sub x@(In@sub 2@Te@sub 3@)@sub 1-x@. The compounds CdIn@sub 2@Te@sub 4@ and In@sub 2@Te@sub 3@ have a band gap of 1.12 eV and 1.0 eV respectively. A band gap modulation toward low energies could be achieved by the incorporation of In in the CdTe lattice. Potential applications for this ternary semiconductor can be thought of in near-IR optoelectronics and photovoltaic heteroestructures. Trying to obtain a gradual incorporation of In in CdTe we produce (CdTe)@sub x@(In@sub 2@Te@sub 3@)@sub 1-x@ thin films by co-sputtering of CdTe and In@sub 2@Te@sub 3@ targets. A previous evaluation of the sputtering yield allow us to control the x parameter through the rf power deliver at each target. We present the results of the chemical, structural and electronic characterization, of a set of eleven thin films, obtained by EDS, X ray diffraction, optical transmission, photoreflectance, photoluminescence, IR and Raman spectroscopies. EDS results indicates that the In content changes between 0 and 38 at%; Cd between 50 and 0 at % and Te between 50 and 62 at %. X ray diffraction showed a gradual change in the CdTe peak positions as In contents increases but for the higher In contents samples were amorphous. Transmission spectroscopy indicates a gradual change of the absorption band edge making difficult to assign the band gap value. Band gap values were obtained by photoreflectance spectroscopy for samples with indium contents up to 17%, indicating a direct band gap. For some samples two transitions were detected. It is possible that for the substrate temperature employed in our system CdTe-rich and In@sub 2@Te@sub 3@-rich compounds were produced with band gap values around 1.43 eV and 1.19 eV, respectively. The results are discussed taking in account the results of the vibrational properties of the thin films. @FootnoteText@@footnote 1@Work partially supported by CONACyT-Mexico.