Quasi-Fermi level splitting and identification of recombination losses from room temperature luminescence in Cu(In1−xGax)Se2 thin films versus optical band gap

2005 ◽  
Vol 480-481 ◽  
pp. 410-414 ◽  
Author(s):  
G.H. Bauer ◽  
R. Brüggemann ◽  
S. Tardon ◽  
S. Vignoli ◽  
R. Kniese
Keyword(s):  
Thin Films ◽  
Fermi Level ◽  
Band Gap ◽  
Room Temperature ◽  
Optical Band Gap ◽  
Quasi Fermi Level ◽  
Level Splitting ◽  
Room Temperature Luminescence

scholarly journals Effects of the Argon Pressure on the Optical Band Gap of Zinc Oxide Thin Films Grown by Nonreactive RF Sputtering

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
M. Acosta ◽  
I. Riech ◽  
E. Martín-Tovar
Keyword(s):  
Thin Films ◽  
Zinc Oxide ◽  
Band Gap ◽  
Room Temperature ◽  
Optical Band Gap ◽  
Rf Sputtering ◽  
Argon Pressure ◽  
Band Gaps ◽  
Zno Thin Films ◽  
Optical Band Gaps

Zinc oxide (ZnO) thin films were grown by nonreactive RF sputtering at room temperature under varying argon pressures (PAr). Their optical band gap was found to increase from 3.58 to 4.34 eV when the argon pressure increases from 2.67 to 10.66 Pa. After annealing at 200°C and 500°C, optical band gaps decrease considerably. The observed widening of the band gap with increasingPArcan be understood as being a consequence of the poorer crystallinity of films grown at higher pressures. Measurements of morphological and electrical properties of these films correlate well with this picture. Our main aim is to understand the effects ofPAron several physical properties of the films, and most importantly on its optical band gap.

scholarly journals Influence of Sodium and Rubidium Postdeposition Treatment on the Quasi-Fermi Level Splitting of Cu(In,Ga)Se2 Thin Films

2018 ◽  
Vol 8 (5) ◽  
pp. 1320-1325 ◽  
Author(s):  
Max Hilaire Wolter ◽  
Benjamin Bissig ◽  
Enrico Avancini ◽  
Romain Carron ◽  
Stephan Buecheler ◽  
...  
Keyword(s):  
Thin Films ◽  
Fermi Level ◽  
Quasi Fermi Level ◽  
Level Splitting

Effects of Different Thermal Treatment on Optical Properties and Microstructure of ZnO Thin Films

2011 ◽  
Vol 197-198 ◽  
pp. 1766-1770 ◽  
Author(s):  
Dong Ping Zhang ◽  
Ping Fan ◽  
Zhuang Hao Zheng ◽  
Li Li Ru ◽  
Jian Jun Huang ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Band Gap ◽  
Constant Temperature ◽  
Room Temperature ◽  
Optical Band Gap ◽  
The Other ◽  
Zno Thin Films ◽  
Zno Films ◽  
Dc Reactive Magnetron Sputtering

ZnO thin films were prepared by DC reactive magnetron sputtering at room temperature. Two of them were annealed with different modes under vacuum condition. One was annealed with constant temperature of 300°C ; the other was annealed with temperature rising step by step from room temperature to 300°C . By comparing the microstructure and optical properties of the as-grown and annealed samples, the effects of different annealing modes on ZnO films performances were revealed. The experiment results investigated that the sample annealed with constant temperature of 300°C has the high grain size and surface roughness. Both of the two annealing modes could release the intrinsic stresses to some degree. The optical band gap of the samples narrowed after annealing, and the two annealed samples have almost the same band gap. Strong green emissions are observed for all the samples, but the emission intensity decreased of the sample annealed with the temperature rising step by step compared with that of other samples.

scholarly journals Influence of temperature on optical proper¬ties of thin films Cu2ZnSnSe4

2018 ◽  
pp. 50-54
Author(s):  
E. V. Maistruk ◽  
I. P. Koziarskyi ◽  
D. P. Koziarskyi ◽  
P. D. Maryanchuk
Keyword(s):  
Thin Films ◽  
Solar Cells ◽  
Absorption Coefficient ◽  
Band Gap ◽  
Room Temperature ◽  
Optical Band Gap ◽  
Materials Science ◽  
Scientific Activity ◽  
Optical Absorption Coefficient ◽  
Effect Of Temperature

The use of solar cells in various fields of science and technology contributes to the development of materials science and scientific activity in this area. Recently, scientists have been researching the optical and electrical properties of materials such as casterite. Casterite is a natural mineral which consists mainly of copper, zinc, tin, sulfur and selenium, that is, elements that are fairly widespread in nature. Therefore, solar cells, developed on the basis of casterite, will have, according to the researchers, a low cost. In addition, casterites belong to direct-gap semiconductors with a band gap of 0.9—1.5 eV and with a large optical absorption coefficient (≈ 104 cm–1). In this work, the authors investigate the effect of temperature on the optical properties of Cu2ZnSnSe4 thin films of casterite obtained by the method of RF magnetron sputtering of previously synthesized material on glass substrates. Optical coefficients were determined by a method based on independent measurement of reflection and transmission coefficients. The reflection coefficient was studied at room temperature, and the transmittance — in the temperature range of 111—290 K. The measurements were made in the wavelength range from 0.9 to 26 µm. The obtained data were used to calculate the absorption coefficient and the band gap of the samples at different temperatures from the range under study. Studies have shown that direct interband optical transitions are observed in Cu2ZnSnSe4 films. The optical band gap at room temperature was 0.92 eV at a temperature coefficient of –1,29∙10–4 eV/K, that is, the optical band gap decreases with temperature, which is typical of classical semiconductors.

scholarly journals Controlling room temperature ferromagnetism and band gap in ZnO nanostructured thin films by varying angle of implantation

RSC Advances ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 6278-6287 ◽  
Author(s):  
Rajesh V. Hariwal ◽  
Hitendra K. Malik ◽  
Ambika Negi ◽  
Asokan Kandasami
Keyword(s):  
Thin Films ◽  
Surface Roughness ◽  
Band Gap ◽  
Room Temperature ◽  
Optical Band Gap ◽  
Room Temperature Ferromagnetism ◽  
Host Lattice ◽  
Zno Thin Films ◽  
Nanostructured Thin Films

The defects in the host lattice play a major role in tuning the surface roughness, optical band gap and the room temperature ferromagnetism of ZnO thin films.

Transparent p- and n-Type Conductive Oxides With Delafossite Structure

2000 ◽  
Vol 623 ◽  
Author(s):  
Hiroshi Yanagi ◽  
Kazushige Ueda ◽  
Shuntaro Ibuki ◽  
Tomomi Hase ◽  
Hideo Hosono ◽  
...  
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Band Gap ◽  
Room Temperature ◽  
Optical Band Gap ◽  
Conducting Oxides ◽  
Transparent Conducting ◽  
Delafossite Structure ◽  
P Type ◽  
Type Conduction

AbstractThin films of CuAlO2, CuGaO2 and AglnO2 with delafossite structure were prepared on sapphire substrates by pulsed laser deposition method. The resulting CuA102 thin films exhibited p-type conduction and the electrical conductivity at room temperature was 0.3 Scm−1. CuGaO2 thin films were grown epitaxially on μ-Al2O3 (001) surface and showed p-type conduction (conductivity at room temperature = 0.06 S cm−1). The optical band gap was estimated to be ∼3.5 eV for CuAlO2 or ∼3.6 eV for CuGaO2. On the other hand, the thin film of Sn doped AglnO2 exhibited n-type conduction. The optical band gap and electrical conductivity at room temperature were ∼4.1 eV and 70 S cm−1, respectively. The recent work demonstrates the validity of our chemical design concept for p- and n-type transparent conducting oxides, providing an opportunity for realization of transparent p-n junction using delafossite-type oxides.

Stability Investigation in the Optical Properties of Thermally Evaporated Ge5Se95-x Znx Thin Films

2015 ◽  
Vol 7 (3) ◽  
pp. 1923-1930
Author(s):  
Austine Amukayia Mulama ◽  
Julius Mwakondo Mwabora ◽  
Andrew Odhiambo Oduor ◽  
Cosmas Mulwa Muiva ◽  
Boniface Muthoka ◽  
...  
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Optical Band Gap ◽  
Thermal Evaporation ◽  
Optical Transition ◽  
Bulk Material ◽  
Band Gap Energy ◽  
Optical Absorbance ◽  
Gap Energy ◽  
Constituent Elements

 Selenium-based chalcogenides are useful in telecommunication devices like infrared optics and threshold switching devices. The investigated system of Ge5Se95-xZnx (0.0 ≤ x ≤ 4 at.%) has been prepared from high purity constituent elements. Thin films from the bulk material were deposited by vacuum thermal evaporation. Optical absorbance measurements have been performed on the as-deposited thin films using transmission spectra. The allowed optical transition was found to be indirect and the corresponding band gap energy determined. The variation of optical band gap energy with the average coordination number has also been investigated based on the chemical bonding between the constituents and the rigidity behaviour of the system’s network.

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