scholarly journals Grain size dependent optical band gap of CdI2 films

2001 ◽  
Vol 24 (3) ◽  
pp. 297-300 ◽  
Author(s):  
Pankaj Tyagi ◽  
A. G. Vedeshwar
Keyword(s):  
Grain Size ◽  
Band Gap ◽  
Optical Band Gap ◽  
Size Dependent

Research on Nanocrystalline Silicon Film Solar Cells

2011 ◽  
Vol 347-353 ◽  
pp. 870-873
Author(s):  
Chun Rong Xue
Keyword(s):  
Grain Size ◽  
Solar Cells ◽  
Band Gap ◽  
Optical Band Gap ◽  
Volume Fraction ◽  
Silicon Film ◽  
Nanocrystalline Silicon ◽  
Processing Parameters ◽  
Crystalline Volume Fraction ◽  
Hydrogen Dilution

Nanocrystalline silicon film has become the research hit of today’ s P-V solar technology. It’s optical band gap was controlled through changing the grain size and crystalline volume fraction for the quanta dimension effect. The crystalline volume fraction in nc-Si:H is modulated by varying the hydrogen concentration in the silane plasma. Also, the crystallinity of the material increases with increasing hydrogen dilution ratio, the band tail energy width of the nc-Si:H concurrently decreases. Two sets of nc-Si:H solar cells were made with different layer thicknesss, their electronic and photonic bandgap, absorption coefficient, optical band gap, nanocrystalline grain size(D), and etc have been stuied. In addition, we discussed the relationship between the stress of nc-Si thin films and H2 ratio. At last nc-Si:H solar cells have been designed and prepared successfully in the optimized processing parameters.

Size dependent optical band gap of ternary I-III-VI2 semiconductor nanocrystals

2009 ◽  
Vol 105 (7) ◽  
pp. 073106 ◽  
Author(s):  
Takahisa Omata ◽  
Katsuhiro Nose ◽  
Shinya Otsuka-Yao-Matsuo
Keyword(s):  
Band Gap ◽  
Optical Band Gap ◽  
Semiconductor Nanocrystals ◽  
Size Dependent

scholarly journals Effect of Deposition Pressure on the Microstructure and Optical Band Gap of Molybdenum Disulfide Films Prepared by Magnetron Sputtering

Coatings ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 570 ◽  
Author(s):  
Gong ◽  
Xiao ◽  
Zhu ◽  
Wang ◽  
Ma
Keyword(s):  
Crystal Structure ◽  
Grain Size ◽  
Surface Morphology ◽  
Magnetron Sputtering ◽  
Band Gap ◽  
Optical Band Gap ◽  
Exciton Energy ◽  
Deposition Pressure ◽  
Electronegativity Difference ◽  
Structure Surface

MoS2 films were prepared via magnetron sputtering under different deposition pressures, and the effects of deposition pressure on the crystal structure, surface morphology, and optical properties of the resulting films were investigated. The results show that the crystallinity of the films first increases and then decreases with increasing pressure. The surface of the films prepared by magnetron sputtering is dense and uniform with few defects. The deposition pressure affects the grain size, surface morphology, and optical band gap of the films. The films deposited at a deposition pressure of 1 Pa revealed remarkable crystallinity, a 30.35 nm grain size, and a 1.67 eV optical band gap. Given the large electronegativity difference between MoS2 molecules and weak van der Waals forces between layers, the MoS2 films are prone to defects at different deposition pressures, causing the exciton energy near defects to decrease and the modulation of the surrounding band.

Single Phase CuO Thin Films Prepared by Thermal Oxidation in Air with Water Vapor

2015 ◽  
Vol 1109 ◽  
pp. 544-548 ◽  
Author(s):  
Jian Bo Liang ◽  
Xu Yang Li ◽  
Naoki Kishi ◽  
Tetsuo Soga
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Optical Properties ◽  
Water Vapor ◽  
Band Gap ◽  
Thermal Oxidation ◽  
Single Phase ◽  
Optical Band Gap ◽  
Structural And Optical Properties ◽  
Oxidation In Air

Single phase CuO films have been successfully synthesized by thermal oxidation of cupper foil in air with water vapor. The structural and optical properties of CuO films were investigated. It is observed that the grain size increases with increasing the oxidation temperature. The optical band gap of CuO film is determined by the transmittance and reflectance spectra.

Properties of Annealed Indium Tin Tantalum Oxide Films Prepared by Reactive Magnetron Sputtering

2013 ◽  
Vol 422 ◽  
pp. 70-74
Author(s):  
Bo Zhang
Keyword(s):  
Grain Size ◽  
Magnetron Sputtering ◽  
Band Gap ◽  
Carrier Concentration ◽  
Room Temperature ◽  
Optical Band Gap ◽  
Tantalum Oxide ◽  
Annealing Treatment ◽  
Glass Substrates ◽  
Near Ir

ndium tin oxide (ITO) and indium tin tantalum oxide (ITTO) films were deposited on glass substrates at room temperature by magnetron sputtering. Properties of the ITO and ITTO films showed a dependence on annealing treatment. ITTO film deposited at room temperature showed the enhancement in (400) orientation and the increasing in grain size. With an increase in annealing temperature, the intensity of XRD peak increased and the grain size showed an evident increasing. The reflection edge in near-IR range and the absorption edge in near-UV range shifted due to the variation in carrier concentration. Ta-doping improved the carrier concentration of the films and widened the corresponding optical band gap. The variations in optical band gap were due to Burstein-Moss effect. The higher value of figure of merit of ITTO films was observed. The tantalum-doped ITO films could find extensive application in some devices.

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.

scholarly journals Polymer Thermal Treatment Production of Cerium Doped Willemite Nanoparticles: An Analysis of Structure, Energy Band Gap and Luminescence Properties

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1118
Author(s):  
Ibrahim Mustapha Alibe ◽  
Khamirul Amin Matori ◽  
Mohd Hafiz Mohd Zaid ◽  
Salisu Nasir ◽  
Ali Mustapha Alibe ◽  
...  
Keyword(s):  
Solid State ◽  
Thermal Treatment ◽  
Band Gap ◽  
Optical Band Gap ◽  
Dopant Concentration ◽  
Blue Emission ◽  
Green Emission ◽  
Band Gap Energy ◽  
Solid State Lighting ◽  
Gap Energy

The contemporary market needs for enhanced solid–state lighting devices has led to an increased demand for the production of willemite based phosphors using low-cost techniques. In this study, Ce3+ doped willemite nanoparticles were fabricated using polymer thermal treatment method. The special effects of the calcination temperatures and the dopant concentration on the structural and optical properties of the material were thoroughly studied. The XRD analysis of the samples treated at 900 °C revealed the development and or materialization of the willemite phase. The increase in the dopant concentration causes an expansion of the lattice owing to the replacement of larger Ce3+ ions for smaller Zn2+ ions. Based on the FESEM and TEM micrographs, the nanoparticles size increases with the increase in the cerium ions. The mean particles sizes were estimated to be 23.61 nm at 1 mol% to 34.02 nm at 5 mol% of the cerium dopant. The optical band gap energy of the doped samples formed at 900 °C decreased precisely by 0.21 eV (i.e., 5.21 to 5.00 eV). The PL analysis of the doped samples exhibits a strong emission at 400 nm which is ascribed to the transition of an electron from localized Ce2f state to the valence band of O2p. The energy level of the Ce3+ ions affects the willemite crystal lattice, thus causing a decrease in the intensity of the green emission at 530 nm and the blue emission at 485 nm. The wide optical band gap energy of the willemite produced is expected to pave the way for exciting innovations in solid–state lighting applications.

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