NANOSTRUCTURED PbTe THIN FILMS ELECTROCHEMICALLY DEPOSITED ON POROUS SILICON SUBSTRATE

摘要

PbTe thin films were electrodeposited on porous silicon substrates from aqueous alkaline solutions of Pb(CH3COO)2, disodiurn salt of ethylendiaminetetraacetic acid (EDTA) and TeO2 by galvanostatic and potentiostatic method. Porous silicon layer (PSL) has presented a nanometric porosity obtained by stain etching for different concentrations of HF and HNO3, characteristic of heavily doped p type silicon. This porosity was analyzed by Atomic Force Microscopy (AFM) images. A strong photoluminescence characteristic for PSL was also evidenced by Raman spectra as a function of the etching time and HNO3 concentration. It was obtained nanostructured PbTe thin films with polycrystalline morphology. The films also presented Pb peaks on X-Ray Diffraction (XRD) spectra depend on the growth process to be galvanostatic or potentiostatic. Films deposited by controlling deposition potential range have shown better crystalline quality. From Scanning Electron Microscopy (SEM) analysis it was observed good films reproducibility that present an average grain size of 100 nm.