  Metal/superconductor/semiconductor (Ag/TlBaCaCuO/CdSe) heterostructures have
been successfully fabricated using pulse-electrodeposition technique. The
electrochemical parameters are optimized and diffusion free growth of CdSe onto
Ag/TlBaCaCuO was obtained by employing under-potential deposition and by
studying nucleation and growth mechanism during deposition. The
heterostructures are characterized by X-ray diffraction (XRD), full-width at
half-maximum (FWHM), scanning electron microscopy (SEM) studies and low
temperature four probe electrical resistivity measurements. After the
deposition of CdSe the critical transition temperature of TlBaCaCuO films was
found be increased from 116.5 K with Jc = 2.1 x 103 A/cm2 to 118.7 K with Jc =
2.3 x 103 A/cm2. When the heterostructure was irradiated with red He-Ne laser
(2 mW), the Tc was further enhanced to 121 K with Jc = 3 x 103 A/cm2. This
increase in superconducting parameters of TlBaCaCuO in Ag/TlBaCaCuO/CdSe
heterostructure has been explained at length in this paper. Keywords.
Electrodeposition; Tl-based cuprate; semiconductor; heterostructures;
electrical properties. PACS Nos 81.15.Pq; 74.72.Gr; 78.40.Fy; 84.37; 73.40
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