ROMJIST Volume 26, No. 2, 2023, pp. 205-217, DOI: 10.59277/ROMJIST.2023.2.07
Cosmin ROMANITAN, Iuliana MIHALACHE, Silviu VULPE, Marius STOIAN, Ioan-Valentin TUDOSE, Raluca GAVRILA, Pericle VARASTEANU, Marian POPESCU, Oana BRINCOVEANU, Nikolay DJOURELOV, Emmanouel KOUDOUMAS, Mirela SUCHEA Relationship Between Structural and Optical Properties in Vanadium Pentoxide
ABSTRACT: Spray pyrolysis technique (SPT) and radio-frequency magnetron sputtering (RF-MS) were used to obtain vanadium oxide (VxOy) layers. The surface morphology was visualized using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Further, the microstructure was assessed by means of X-ray diffraction (XRD), showing the formation of orthorhombic V2O5 (α-V2O5) with high crystallinity by SPT. On the other side, RF-MS at low substrate temperature led to α-V_2 O_5 with low crystallinity, even at 800 swipes which according to the Kiessig interference fringes from X-ray reflectivity indicates a film thickness of 70 nm. Finally, diffuse reflectance spectroscopy (DRS) absorbance was used to investigate the optical properties for the obtained samples, noting important differences regarding the bandgap energy between SPT and RF-MS depositions. To explain the observed discrepancies, X-ray photoelectron spectroscopy (XPS) was performed, thus obtaining a correlation of the bandgap to the oxidation state of vanadium ions. KEYWORDS: RF magnetron sputtering; spray pyrolysis technique; vanadium oxide; X-ray diffractionRead full text (pdf)