THICKNESS AND OXYGEN PRESSURE DEPENDENT OPTICAL PROPERTIES OF NIOBIUM OXIDE THIN FILMS

1999 ◽  
Vol 13 (04) ◽  
pp. 411-418 ◽  
Author(s):  
M. GHANASHYAM KRISHNA ◽  
A. K. BHATTACHARYA
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Optical Properties ◽  
Band Gap ◽  
Oxygen Pressure ◽  
Absorption Edge ◽  
Niobium Oxide ◽  
Critical Value ◽  
Oxide Thin Films ◽  
Observed Behaviour

The optical properties of niobium oxide thin films in the thickness range between 75 and 200 nm have been studied. The films were deposited by dc magnetron sputtering and it was found that the refractive index, extinction coefficient and the absorption edge were all strongly dependent on the oxygen pressure during sputtering as well as the thickness of the deposited films. In general, the low thickness films had a lower refractive index than the high thickness films. The highest refractive index obtained was 2.46 at a wavelength of 650 nm for the film deposited at an oxygen pressure of 2 mTorr and to a thickness of 200 nm. The low thickness (~ 120 nm) films showed an initial decrease in refractive index, with oxygen pressure increasing above a critical value. The thicker films, however showed the opposite behaviour, increasing initially and decreasing marginally above the same critical pressure. The absorption edge showed a critical value of thickness above and below which it decreased and a critical value of oxygen pressure during sputtering above and below which it increased. The band gap values varied from 3.3 to 3.6 eV with the thinner films showing the higher band gap. The observed behaviour was explained using the single effective Lorentzian oscillator model.

Preparation and Properties of Niobate Thin Films from Nanosheets

2010 ◽  
Vol 177 ◽  
pp. 201-203
Author(s):  
Jing Chu ◽  
Yu Lin Li ◽  
Bing Xu ◽  
Na Zhang ◽  
Qiang Li
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Phase Structure ◽  
Niobium Oxide ◽  
Oxide Thin Films ◽  
Transmittance Spectra ◽  
Different Thickness ◽  
Soaking Temperature

Niobium oxide thin films were successfully synthesized starting from niobate nanosheets. The microstructure of as-prepared nanosheets was observed by TEM. The morphology of niobate thin films was investigated by SEM. The phase structure was determined by XRD. The transmittance spectra of as-obtained niobium oxide thin films were measured, and the optical properties were studied. The influences of different thickness on optical properties were also analyzed. As-prepared niobium thin films were treated by being heated at different temperature. The effects of soaking temperature on the structure and optical properties of niobium oxide thin films were discussed in detail.

Optical Properties of NiO Thin Films: A Potential Material for Optoelectronic Devices

2012 ◽  
Vol 488-489 ◽  
pp. 103-108 ◽  
Author(s):  
Manisha Tyagi ◽  
Monika Tomar ◽  
Vinay Gupta
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Optical Properties ◽  
Substrate Temperature ◽  
Band Gap ◽  
Urbach Energy ◽  
Rf Sputtering ◽  
Blue Shift ◽  
Structural Disorder ◽  
Near Ir

The influence of substrate temperature on the UV-Visible-near-IR optical properties, namely the band gap, the Urbach energy and the refractive index of NiO thin films deposited by RF sputtering has been investigated. The optical band gap of thin films showed the blue-shift in the transmission spectra with increase in the substrate temperature which is related to variation in carrier concentration of the deposited films. Urbach energy (EU) values indicate that the films deposited at 400 oC substrate temperature show least structural disorder. The refractive index of the films is found to decrease continuously with increase in the substrate temperature at all photon energies in the visible and near-IR region, and is attributed to the decreasing packing density of the films. Introduction

Effects of Nitrogen Doping on Optical Properties of Tungsten Oxide Thin Films

2012 ◽  
Vol 616-618 ◽  
pp. 1773-1777
Author(s):  
Xi Lian Sun ◽  
Hong Tao Cao
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Optical Properties ◽  
Band Gap ◽  
Tungsten Oxide ◽  
Nitrogen Doping ◽  
Optical Band Gap ◽  
Band Gap Energy ◽  
Gap Energy ◽  
Tungsten Oxide Thin Films

In depositing nitrogen doped tungsten oxide thin films by using reactive dc pulsed magnetron sputtering process, nitrous oxide gas (N2O) was employed instead of nitrogen (N2) as the nitrogen dopant source. The nitrogen doping effect on the structural and optical properties of WO3 thin films was investigated by X-ray diffraction, transmission electron microscopy and UV-Vis spectroscopy. The thickness, refractive index and optical band gap energy of these films have been determined by analyzing the SE spectra using parameterized dispersion model. Morphological images reveal that the films are characterized by a hybrid structure comprising nanoparticles embeded in amorphous matrix and open channels between the agglomerated nanoparticles. Increasing nitrogen doping concentration is found to decrease the optical band gap energy and the refractive index. The reduced band gaps are associated with the N 2p orbital in the N-doped tungsten oxide films.

Optical Properties of PZT, PLZT, and PNZT Thin Films

1991 ◽  
Vol 243 ◽  
Author(s):  
Chien H. Peng ◽  
Jhing-Fang Chang ◽  
Seshu B. Desu
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Optical Properties ◽  
Band Gap ◽  
Band Gap Energy ◽  
Gap Energy ◽  
Pzt Films ◽  
Direct Band ◽  
Band Transition ◽  
La Doped

AbstractOptical properties were investigated for undoped, La-doped, and Nd-doped Pb(ZrxTi1-x)O3 thin films deposited on sapphire substrates by metalorganic decomposition (MOD) process. Refractive index and extinction coefficient of these films were calculated from transmission spectra in the wavelength range of 300 to 2000 nm. The packing densities of these films were calculated from the refractive index data by using the effective medium approximation. Band gap energies of these films were also reported under the assumption of direct band-to-band transition. The refractive index and band gap energy of PZT films showed a linear dependence on Zr/Ti ratio. The refractive index decreased, while the band gap energy increased with increasing zirconium content. It was also found that both La-doped and Nd-doped PZT films had higher refractive indices than those of undoped PZT films with the same Zr/Ti ratio (50/50).

QUANTUM CONFINEMENT EFFECTS ON THE OPTICAL PROPERTIES OF ION BEAM SPUTTERED NICKEL OXIDE THIN FILMS

2001 ◽  
Vol 15 (02) ◽  
pp. 191-200 ◽  
Author(s):  
M. GHANASHYAM KRISHNA ◽  
A. K. BHATTACHARYA
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Nickel Oxide ◽  
Band Gap ◽  
Quantum Confinement ◽  
Ion Beam ◽  
Confinement Effects ◽  
Oxide Thin Films ◽  
Quantum Confinement Effects ◽  
Nickel Oxide Thin Films

Quantum confinement effects on the optical properties of ion beam sputtered nickel oxide thin films are reported. Thin films with crystallite sizes in the range 9 to 14 nm have been deposited on to fused silica substrates. There is an increase in band gap, from 3.4 to 3.9 eV, and a decrease in refractive index, from 2.4 to 1.6, with decrease in crystallite size, that can be attributed to quantum confinement effects. The effective mass approximation has been used to explain the observed behaviour in band gap variation.

scholarly journals Effect of gamma irradiation on structural, morphological and optical properties of p-quaterphenyl thin films

2018 ◽  
Vol 14 (2) ◽  
pp. 5624-5637
Author(s):  
A.A. Attia ◽  
M.M. Saadeldin ◽  
K. Sawaby
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Optical Properties ◽  
Surface Morphology ◽  
Absorption Coefficient ◽  
Gamma Irradiation ◽  
Band Gap ◽  
Optical Band Gap ◽  
Thermal Evaporation Method ◽  
Single Oscillator Model

Para-quaterphenyl thin films were deposited onto glass and quartz substrates by thermal evaporation method. p-quaterphenyl thin films wereexposed to gamma radiation of Cobat-60 radioactive source at room temperature with a dose of 50 kGy to study the effect of ?-irradiation onthe structure and the surface morphology as well as the optical properties of the prepared films. The crystalline structure and the surface morphology of the as-deposited and ?-irradiated films were examined using the X-ray diffraction and the field emission scanning electron microscope. The optical constants (n & k) of the as-deposited and ?-irradiated films were obtained using the transmittance and reflectance measurements, in the wavelength range starting from 250 up to 2500 nm. The analysis of the absorption coefficient data revealed an allowed direct transition with optical band gap of 2.2 eV for the as-deposited films, which decreased to 2.06 eV after exposing film to gamma irradiation. It was observed that the Urbach energy values change inversely with the values of the optical band gap. The dispersion of the refractive index was interpreted using the single oscillator model. The nonlinear absorption coefficient spectra for the as-deposited and ?-irradiated p-quaterphenyl thin films were obtained using the linear refractive index.

Properties of TiO2 Thin Film Prepared by Sol-Gel Dip Coating

2015 ◽  
Vol 723 ◽  
pp. 528-531
Author(s):  
Jun Wang ◽  
Ling Yun Bai
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Refractive Index ◽  
Optical Properties ◽  
Band Gap ◽  
Optical Band Gap ◽  
Sol Gel ◽  
Dip Coating ◽  
Gel Method ◽  
Glass Substrates

TiO2 thin films were prepared on glass substrates by sol-gel method. The effect of withdraw speed on the thickness and optical properties of TiO2 thin films was investigated. The films were transparent in the visible wavelength. The thickness of the TiO2 films was increased from 90 nm for the withdraw speed of 1000 μm/s to 160 nm for the withdraw speed of 2000 μm/s. While, The refractive index of the TiO2 thin film decreased from 2.38 to 2.07. It may be due to the porosity of the film was increased. The optical band-gap of the films was around 3.45 eV.

scholarly journals Structural and Optical Properties of Chemical Bath Deposited Silver Oxide Thin Films: Role of Deposition Time

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
A. C. Nwanya ◽  
P. E. Ugwuoke ◽  
B. A. Ezekoye ◽  
R. U. Osuji ◽  
F. I. Ezema
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Band Gap ◽  
Deposition Time ◽  
Silver Oxide ◽  
Energy Levels ◽  
Complexing Agent ◽  
Oxide Thin Films ◽  
Glass Substrates ◽  
Time Changes

Silver oxide thin films were deposited on glass substrates at a temperature of 50°C by chemical bath deposition technique under different deposition times using pure AgNO3precursor and triethanolamine as the complexing agent. The chemical analysis based on EDX technique shows the presence of Ag and O at the appropriate energy levels. The morphological features obtained from SEM showed that the AgxO structures varied as the deposition time changes. The X-ray diffraction showed the peaks of Ag2O and AgO in the structure. The direct band gap and the refractive index increased as the deposition time increased and was in the range of 1.64–1.95 eV and 1.02–2.07, respectively. The values of the band gap and refractive index obtained indicate possible applications in photovoltaic and photothermal systems.

Effects of preparation conditions on the optical properties of niobium oxide thin films

2019 ◽  
Vol 50 (1) ◽  
pp. 22-27
Author(s):  
Imtiaz Ahmad ◽  
Muhammad Ashraf ◽  
Yaqoob Khan ◽  
Ehsan E. Khawaja ◽  
Zulfiqar Ali ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Niobium Oxide ◽  
Oxide Thin Films ◽  
Preparation Conditions
Sign in / Sign up

Export Citation Format

Share Document