Morphological, optical, and electrical properties of RF-sputtered zinc telluride thin films for electronic and optoelectronic applications

• Published in: AIP advances Vol. 12; no. 11; pp. 115013 - 115013-7
• Main Authors: Panaitescu, Ana-Maria, Antohe, Iulia, Răduță, Ana-Maria, Iftimie, Sorina, Antohe, Ștefan, Mihăilescu, Cristian Nicolae, Antohe, Vlad-Andrei
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 01.11.2022; AIP Publishing LLC
• Subjects: Aluminum; Argon; Charge transport; Copper; Current voltage characteristics; Electrical measurement; Electrical properties; Electrodes; Evaluation; Intermetallic compounds; Magnetron sputtering; Morphology; Optical glass; Optical properties; Optoelectronics; Radio frequency; Room temperature; Silver; Substrates; Thickness; Thin films; Zinc telluride; Zinc tellurides
• ISSN: 2158-3226; 2158-3226
• DOI: 10.1063/5.0116999

Zinc telluride (ZnTe) thin films were deposited by radio-frequency magnetron sputtering (RF-MS) onto optical glass coated by a silver–copper (Ag:Cu) thin film representing the back-electrode, and they were subsequently electrically contacted with an aluminum (Al) layer acting as the top-electrode. The RF-MS procedure was carried out at 50 W in argon (Ar) gas atmosphere kept at 2.5 × 10−3 mbar working pressure for 75 min at a substrate temperature of 220 °C kept constant during deposition. Morphological investigations by scanning electron microscopy allowed a first evaluation of the ZnTe film’s thickness. Optical characterization was then performed via absorption and transmission measurements in the spectral range between 300 and 1500 nm at room temperature. Subsequently, the thickness and bandgap energy of the ZnTe thin film were evaluated to be ∼508 nm and ∼2.13 eV, respectively. Moreover, they revealed high transmittance in infrared and near infrared regions of the electromagnetic spectrum. Then, the electrical measurements of Ag:Cu/ZnTe/Al “sandwich” structure (current–voltage characteristics) at six temperatures ranging from 303 to 354 K were performed, allowing the identification of the charge transport mechanisms through the structure along with their corresponding parameters. Based on the excellent optical and electrical properties, these ZnTe thin films show great potential as candidates for performant small-wavelength photodetectors.