Morphology and stress study of nanostructured porous silicon as a substrate for PbTe thin films growth by electrochemical process

Abstract

Porous silicon layers (PSL) were produced by stain etching from a HF:HNO3 500:1 mixture with etching time varying in the range of 1 up to 10 min. The samples have presented nanometric porosity as a function of etching time, characteristic of heavily doped p type silicon. The residual stress and the correlation length of the layers were obtained through the analysis of the micro-Raman spectra using a phonon confinement model including a term to account for the amorphous phase. The residual compressive stress tends to increase as expected due to the contribution of smaller crystallites to be more representative as the etching time increases. PbTe thin films were electrodeposited on PSL from aqueous alkaline solutions of Pb(CH3COO)2, disodium salt of ethylendiaminetetraacetic acid (EDTA) and TeO2 by galvanostatic and potentiostatic method. It was also obtained nanostructured PbTe thin films with polycrystalline morphology evidenced by X-ray Diffraction (XRD) spectra. Scanning Electron Microscopy (SEM) analysis has demonstrated good films reproducibility with an average grain size of 100 nm

Te-Embedded Nanocrystalline PbTe Thick Films: Structure and Thermoelectric Properties Relationship

“…On the other hand, the solubility of Te ions (i.e., TeO 3 2− ) is much higher in an alkaline solution. The electrodeposition of PbTe films in alkaline solution was investigated by several groups [29][30][31][32][33][34]. Unfortunately, all of these works demonstrated the few-micron thick PbTe films and only few works investigated their thermoelectric performance.…”

Electrodeposition of Dense Lead Telluride Thick Films in Alkaline Solutions

“…20 Miranda et al electrodeposited PbTe thin films with the grain size of 100 nm. 22 Although these works investigated the electrodeposition of PbTe, these works are limited to thin films with low controllability of crystallinity and composition. Additionally, the rate of deposition was significant low due to low TeO 3 2− ions in the electrolytes.…”