Blue-shift in optical bandgap of sprayed nanocrystalline Cu2ZnSnS4 thin films induced by 200 MeV Xe swift heavy ions irradiation

Vanadium has many oxides (VO2 , V2O3 , V2O4 , V6O13 and V2O5 ) due to high oxidation state. Properties of the vanadium oxide thin films can be changed by pressure, doping and strain. Ion irradiation can transform the phase, mix the two solid materials, form epitaxial crystallization and create nanostructure etc. in the materials. Purpose of our study was to observe the effect of swift heavy ions (SHIs) irradiation on vanadium oxide thin films. Thin films of vanadium oxide were deposited on the Si substrate by reactive RF sputtering technique. As-deposited thin films were irradiated by swift heavy ions (100 MeV Ag ions) at different fluences at room temperature. The effect of ions irradiation was studied by using grazing incidence X-ray diffraction (GIXRD), Fourier transform infrared spectroscopy (FTIR) and UV-vis-NIR spectrophotometer characterization techniques. GIXRD pattern revealed that swift heavy ions can induce the phase transformation (V6O13 to V2O3 ) in the films. FTIR characterization showed that δ(V=O) stretching mode at 1020 cm-1 shifted to the lower wave number side. Optical properties showed blue shift in the absorption spectra at the higher fluences. These shifting are due to the lowering of vanadium’s oxidation state in the thin films. This change in oxidation state of vanadium transforms the phase of the films. Irradiation with SHIs can transform the phase along with enhancement in the crystallinity of the vanadium oxide films.

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Blue shift in the optical bandgap of tin oxide thin films by controlling oxygen-to-argon gas flow ratio

Functional Materials Letters ◽

10.1142/s1793604715500149 ◽

2015 ◽

Vol 08 (01) ◽

pp. 1550014 ◽

Cited By ~ 3

Author(s):

Meenakshi ◽

Sanjeev Gautam ◽

Keun Hwa Chae ◽

Ik-Jae Lee ◽

Hyun-Joon Shin ◽

...

Keyword(s):

Thin Films ◽

Tin Oxide ◽

Gas Flow ◽

Blue Shift ◽

Optical Bandgap ◽

Visible Range ◽

Flow Ratio ◽

Argon Gas ◽

Tauc Plot ◽

Gas Flow Ratio

Tin oxide ( SnO 2) thin films were deposited by radio-frequency (RF) magnetron sputtering on silicon and glass substrates at different oxygen-to-argon gas-flow ratio ( O 2-to- Ar = 0%, 10%, 20%, 30% and 50%). All films were deposited at room temperature and fixed working pressures, 10 mTorr. X-ray diffraction (XRD) measurement suggests that all films were crystalline in nature except film deposited only in argon environment. The transparency of all of the films was more than 85% in the visible range except the film deposited only in the argon environment. Atomic force microscopy results showed that the surface of all the films were highly flat and smooth. The optical bandgap, estimated by Tauc plot was increased with oxygen environment. Blue shift was observed in the absorption edge and was accounted to decrease in the oxygen vacancies and dangling bonds.

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