Evaluation of semiconductor materials by hydrothermal synthesis

Abstract

The present work describes the obtaining of semiconductor materials with kesterite structure by a hydrothermal methodology. The obtained kesterite has a structural modification of the conventional Cu2ZnSnS4 structure with the insertion of titanium instead of tin, in order to obtain Cu2ZnTiS4. The precursors of this material, metallic salts of copper, zinc acetate, titanium butoxide and thiourea were added in a hermetic steel reactor, controlling time (24 hours, 48 hours and 72 hours) and temperature (200 °C — 300 °C). To evaluate the synthesis, the materials obtained were analysed by different characterization techniques (X-ray diffraction, scanning electron microscopy, solid state impedance). The results show that material with the conditions of synthesis 48 hours and 300 °C, exhibit the best textural and electrical results in terms of economy process. The X-ray diffraction analysis shows secondary phases, which can possibly be eliminated with a thermal treatment, since most of the secondary phases (such ZnS and Cu2S) can be eliminated by combustion in an inert atmosphere. The results showed that the increase in the temperature of synthesis decreases the formation of amorphous agglomerates, improving the morphology of the material. The characterization of the materials showed that the Cu2ZnSnS4 phase is possible to obtain by hydrothermal synthesis.

Mathematical Models to Determine the Conductivity of a Cztis Photovoltaic Material as a Function of the Synthesis Temperature

“…With X-ray Diffraction (XRD) and Raman spectroscopy, the kesterite phase of the material was identified, likewise, with Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) the homogeneity, the particle size and roughness of the material was determined. On the other hand, with solid state impedance spectroscopy (IS), the corresponding magnitudes were obtained to be able to classify the different CZTiS samples as semiconductor materials (3,4), thus observing a relationship between the roughness of the material and its electrical behavior. Statistical analyzes by means of variance and mathematical models allowed validating the data obtained and interpolating the conductive behavior of the CZTiS material, (5-7).…”