Electronic structure and localized states in amorphous Si and hydrogenated amorphous Si

2019 ◽  
Vol 21 (24) ◽  
pp. 13248-13257 ◽  
Author(s):  
Reza Vatan Meidanshahi ◽  
Stuart Bowden ◽  
Stephen M. Goodnick
Keyword(s):  
Electronic Structure ◽  
Band Gap ◽  
Localized States ◽  
Amorphous Si ◽  
Hydrogenated Amorphous

Calculated DOS of a-Si:H close to the band gap for different H concentrations in the case of (a) thermodynamic and (b) kinetic H addition.

Electronic Structure of Amorphous Silicon

1997 ◽  
Vol 491 ◽  
Author(s):  
G. Allan ◽  
C. Delerue ◽  
M. Lannoo
Keyword(s):  
Electronic Structure ◽  
Amorphous Silicon ◽  
Tight Binding ◽  
Localized States ◽  
Band Offset ◽  
Valence Band Offset ◽  
Tight Binding Approximation ◽  
Exponential Tails ◽  
Si Model ◽  
Hydrogenated Amorphous

ABSTRACTThe electronic structure of a continuous network model of tetrahedrally bonded amorphous silicon (a-Si) and of a model hydrogenated amorphous silicon (a-Si:H) that we have built from the a-Si model are calculated in the tight binding approximation. The band edges near the gap are characterized by exponential tails of localized states induced mainly by the variations in bond angles. The spatial localization of the states is compared between a-Si and a-Si:H. Valence band offset between the amorphous and the crystalline phases is calculated.

scholarly journals Influence of electronic structure on visible light photocatalytic activity of nitrogen-doped TiO2

RSC Advances ◽  
2017 ◽  
Vol 7 (4) ◽  
pp. 1887-1898 ◽  
Author(s):  
Daigo Kusano ◽  
Masato Emori ◽  
Hiroshi Sakama
Keyword(s):  
Electronic Structure ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Band Gap ◽  
Sol Gel ◽  
Valence Band Maximum ◽  
Localized States ◽  
Band Maximum ◽  
Nitrogen Doped ◽  
Visible Light Photocatalytic

N-doped TiO2 was synthesized by sol–gel method from precursor solutions with or without urea and post calcination in NH3 gas. Localized states associated with N were successfully found at 0.24 eV to 0.34 eV above valence band maximum in the band gap.

New Insights into the Nature of the Band Gap of CuGeO3 Nanoparticles: Synthesis, Electronic Structure, and Optical and Photocatalytic Properties

2019 ◽  
Author(s):  
Victor Y. Suzuki ◽  
Luís Henrique Cardozo Amorin ◽  
Natália H. de Paula ◽  
Anderson R. Albuquerque ◽  
Julio Ricardo Sambrano ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Band Gap ◽  
Material Design ◽  
Photocatalytic Properties ◽  
Critical Parameters ◽  
Synthetic Approach ◽  
Microwave Assisted ◽  
Theoretical Approaches ◽  
Nanoparticles Synthesis ◽  
First Time

<p>We report, for the first time, new insights into the nature of the band gap of <a>CuGeO<sub>3</sub> </a>(CGO) nanocrystals synthesized from a microwave-assisted hydrothermal method in the presence of citrate. To the best of our knowledge, this synthetic approach has the shortest reaction time and it works at the lowest temperatures reported in the literature for the preparation of these materials. The influence of the surfactant on the structural, electronic, optical, and photocatalytic properties of CGO nanocrystals is discussed by a combination of experimental and theoretical approaches, and that results elucidates the nature of the band gap of synthetized CGO nanocrystals. We believe that this particular strategy is one of the most critical parameters for the development of innovative applications and that result could shed some light on the emerging material design with entirely new properties.</p> <p><b> </b></p>

scholarly journals Improving the ZT of SnTe using electronic structure engineering: unusual behavior of Bi dopant in the presence of Pb as a co-dopant

2021 ◽  
Vol 2 (19) ◽  
pp. 6267-6271 ◽  
Author(s):  
U. Sandhya Shenoy ◽  
D. Krishna Bhat
Keyword(s):  
Electronic Structure ◽  
Synergistic Effect ◽  
Band Gap ◽  
Resonance Level ◽  
Unusual Behavior ◽  
Level Increase ◽  
Structure Engineering

Extraordinary tuning of electronic structure of SnTe by Bi in the presence of Pb as a co-adjuvant dopant. Synergistic effect of resonance level, increase in the band gap, valence and conduction sub-bands convergence leads to enhanced TE performance.

Optical constants of rf sputtered hydrogenated amorphous Si

1979 ◽  
Vol 20 (2) ◽  
pp. 716-728 ◽  
Author(s):  
Eva C. Freeman ◽  
William Paul
Keyword(s):  
Optical Constants ◽  
Amorphous Si ◽  
Hydrogenated Amorphous

Electronic structure engineering of tin telluride through co-doping of bismuth and indium for high performance thermoelectrics: a synergistic effect leading to a record high room temperature ZT in tin telluride

2019 ◽  
Vol 7 (16) ◽  
pp. 4817-4821 ◽  
Author(s):  
U. Sandhya Shenoy ◽  
D. Krishna Bhat
Keyword(s):  
Electronic Structure ◽  
Synergistic Effect ◽  
Band Gap ◽  
High Performance ◽  
Room Temperature ◽  
Band Offset ◽  
Valence Band Offset ◽  
Co Doping ◽  
Tin Telluride ◽  
Structure Engineering

Resonance states due to Bi and In co-doping, band gap enlargement, and a reduced valence-band offset in SnTe lead to a record high room-temperature ZT.

scholarly journals DFT Study of the Electronic Structure of Cubic-SiC Nanopores with a C-Terminated Surface

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
M. Calvino ◽  
A. Trejo ◽  
M. I. Iturrios ◽  
M. C. Crisóstomo ◽  
Eliel Carvajal ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Band Gap ◽  
Density Functional ◽  
Surface Passivation ◽  
Phase Changes ◽  
Surface Relaxation ◽  
Oh Radicals ◽  
Functional Theory ◽  
Band Gap Engineering ◽  
Chemical Surface

A study of the dependence of the electronic structure and energetic stability on the chemical surface passivation of cubic porous silicon carbide (pSiC) was performed using density functional theory (DFT) and the supercell technique. The pores were modeled by removing atoms in the [001] direction to produce a surface chemistry composed of only carbon atoms (C-phase). Changes in the electronic states of the porous structures were studied by using different passivation schemes: one with hydrogen (H) atoms and the others gradually replacing pairs of H atoms with oxygen (O) atoms, fluorine (F) atoms, and hydroxide (OH) radicals. The results indicate that the band gap behavior of the C-phase pSiC depends on the number of passivation agents (other than H) per supercell. The band gap decreased with an increasing number of F, O, or OH radical groups. Furthermore, the influence of the passivation of the pSiC on its surface relaxation and the differences in such parameters as bond lengths, bond angles, and cell volume are compared between all surfaces. The results indicate the possibility of nanostructure band gap engineering based on SiC via surface passivation agents.

scholarly journals Field Effect on Crystal Phase of Silicon in Si/CeO2/SiO2Structure

2008 ◽  
Vol 2008 ◽  
pp. 1-4
Author(s):  
Dmitry E. Milovzorov
Keyword(s):  
Electronic Structure ◽  
Spatial Distribution ◽  
Band Gap ◽  
Buffer Layer ◽  
Field Effect ◽  
Cerium Dioxide ◽  
Silicon Film ◽  
Crystal Phase ◽  
Great Role ◽  
Defect Levels

The structural, optical, and conductivity properties of silicon film deposited on cerium dioxide buffer layer were studied. The electronic structure of system consists of various defect levels inside band gap. The temperature spatial distribution plays a great role in silicon crystallization. The field destruction of crystal phase and its restoration, after annealing, were investigated.

Light-Induced Effects on Fluorinated Amorphous and Microcrystalline Silicon Films

1996 ◽  
Vol 420 ◽  
Author(s):  
Hong-Seok Choi ◽  
Keun-Ho Jang ◽  
Jhun-Suk Yoo ◽  
Min-Koo Han
Keyword(s):  
Band Gap ◽  
Vapor Deposition ◽  
Optical Band Gap ◽  
Silicon Film ◽  
Hydrogenated Amorphous Silicon ◽  
Chemical Vapor ◽  
Rf Plasma ◽  
Microcrystalline Silicon ◽  
Amorphous Silicon Film ◽  
Hydrogenated Amorphous

AbstractThe fluorinated amorphous and microcrystalline silicon (a,μc-Si:H;F) films have been prepared by rf plasma enhanced chemical vapor deposition (PECVD) with SiH 4 and SiF 4 gas mixtures. The stretching Si-O (1085 cm-1) and SiH2 (2100 cm-1) bands estimated from infrared (IR) spectroscope data have related to the evolution of crystallinity and the optical band gap was shifted by introducing Si-O bonds. The sub-band gap absorption coefficient in a,μc-Si:H;F films was about one order lower than that in hydrogenated amorphous silicon film (a-Si:H). The subband gap absorption in a-Si:H;F film was comparable to that in tic-Si:H;F films. The lightinduced degradation of a,μc-Si:H;F films were also suppressed.

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