scholarly journals Correlation of film thickness to optical band gap of Sol-gel derived Ba0.9Gd0.1TiO3 thin films for optoelectronic applications

2017 ◽  
Vol 162 ◽  
pp. 01042
Author(s):  
Yen Chin Teh ◽  
Ala’eddin A. Saif ◽  
Zul Azhar Zahid Jamal ◽  
Prabakaran Poopalan
2004 ◽  
Vol 11 (06) ◽  
pp. 559-562
Author(s):  
M. RUSOP ◽  
S. ADHIKARI ◽  
A. M. M. OMER ◽  
S. ADHIKARY ◽  
H. UCHIDA ◽  
...  

This paper reports the band gap shifting due to nitrogen ( N 2) doping, microwave power and composition gas pressure of nitrogenated amorphous carbon ( a - C : N ) thin films deposited by newly-developed surface wave microwave plasma chemical vapor deposition (SWMP-CVD). Results show that the optical band gap decreased from 4.1 eV to 2.4 eV corresponding to the increase of N 2 doping from 0 to 5% in the gas ratio. However, further increase of N 2 doping beyond 5% did not decrease the band gap. It was found that composition gas pressure and launched MW power during film deposition also largely control the optical band gap. Investigation of annealing effects on optical band gap and film thickness of the N 2 doped films revealed that both band gap and film thickness decrease significantly with increase of annealing temperature. The optical band gap decreased from 2.4 eV to 1.1 eV, while film thickness decreases from 320 nm to 50 nm corresponding to 200 to 400°C annealing temperature. The results revealed that the properties of a - C : N can be tuned by changing the annealing temperature, composition gas pressure and microwave power of the SWMP-CVD system.


2015 ◽  
Vol 723 ◽  
pp. 528-531
Author(s):  
Jun Wang ◽  
Ling Yun Bai

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.


2007 ◽  
Vol 21 (12) ◽  
pp. 2017-2032 ◽  
Author(s):  
M. ANWAR ◽  
S. A. SIDDIQI ◽  
I. M. GHAURI

The fundamental absorption edge of SnO 2 amorphous thin films has been investigated. It has been observed that the optical energy gap decreases with the increase in film thickness, substrate temperature and post deposition annealing. The results are analysed by assuming optical absorption by non-direct transition. The decrease in optical band gap with increase in film thickness may be interpreted in terms of the incorporation of oxygen vacancies in the SnO 2 lattice. The decrease in optical energy due to the increase in substrate temperature may be ascribed to the release of trapped electrons by thermal energy or by the outward diffusion of the oxygen-ion vacancies, which are quite mobile even at low temperatures. The decrease in optical band gap due to annealing may be due to the formation of tin species of lower oxidation state.


2005 ◽  
Vol 486-487 ◽  
pp. 65-68 ◽  
Author(s):  
Sang Wook Lee ◽  
Hyun Suk Jung ◽  
Dong Wook Kim ◽  
Kug Sun Hong

5, 10, and 30 nm thickness of transparent TiO2 thin films were fabricated using sol-gel process, and the influence of film thickness on the photocatalytic property was investigated. The increase in film thickness was found to enhance the photocatalytic property of the films. Photocatalytic properties of each film were estimated by decomposition of stearic acid. The amount of decomposed stearic acid increased with film thickness (5 - 30 nm). For the case of 30 nm thickness film, the stearic acid was decomposed perfectly in twelve minutes. UV-vis spectra and photocurrents of each film clearly showed that the photoactivities of TiO2 films were related to the amount of absorbed UV light and band gap shift.


Optik ◽  
2015 ◽  
Vol 126 (5) ◽  
pp. 575-577 ◽  
Author(s):  
Zayed A. Alahmed ◽  
H.A. Albrithen ◽  
Ahmed A. Al-Ghamdi ◽  
F. Yakuphanoglu

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