Valence and Conduction Band State Densities of Crystalline and Amorphous Ge as Seen via Photoelectron Spectroscopy

1974 ◽  
Author(s):  
D. E. Eastman ◽  
J. L. Freeouf ◽  
M. Erbudak
Keyword(s):  
Conduction Band ◽  
Photoelectron Spectroscopy ◽  
Conduction Band State ◽  
Band State ◽  
State Densities

scholarly journals Comparative study for colloidal quantum dot conduction band state calculations

2006 ◽  
Vol 88 (14) ◽  
pp. 143108 ◽  
Author(s):  
Jun-Wei Luo ◽  
Shu-Shen Li ◽  
Jian-Bai Xia ◽  
Lin-Wang Wang
Keyword(s):  
Quantum Dot ◽  
Comparative Study ◽  
Conduction Band ◽  
Conduction Band State ◽  
Band State ◽  
Colloidal Quantum Dot

ALD Deposited Al2 O3 Films on 6H-SiC(0001) after Annealing in Hydrogen Atmosphere

2005 ◽  
Vol 483-485 ◽  
pp. 559-562 ◽  
Author(s):  
Kun Yuan Gao ◽  
Thomas Seyller ◽  
Konstantin V. Emtsev ◽  
Lothar Ley ◽  
Florin Ciobanu ◽  
...  
Keyword(s):  
Conduction Band ◽  
Photoelectron Spectroscopy ◽  
Depth Profiling ◽  
Atomic Layer ◽  
Hydrogen Atmosphere ◽  
Band Edge ◽  
Conduction Band Edge ◽  
Strong Increase ◽  
Admittance Spectroscopy ◽  
Spectroscopy Measurement

Atomic Layer Deposited Al2O3 films on hydrogen-terminated 6H-SiC(0001) were annealed in hydrogen atmosphere and characterized by admittance spectroscopy measurement and photoelectron spectroscopy (PES). The resultant density of interface trap (Dit) from admittance spectroscopy measurement is reduced near mid gap, but increases strongly towards the conduction band edge. Systematic PES measurements show that hydrogen annealing introduces Si4+ as a new component besides Si0 and Si+. Using different electron escape depths for photon electrons, depth profiling of Si in its different oxidation states was performed. The result indicates the formation of a top SiO2 layer and a rougher interfacial layer containing more Si+ and Si4+ which could be responsible for the strong increase of Dit just below the conduction band edge.

Experimental and First-Principles Studies of the Band Alignment at the HfO2/4H-SiC (0001) Interface

2006 ◽  
Vol 527-529 ◽  
pp. 1071-1074 ◽  
Author(s):  
Carey M. Tanner ◽  
Jong Woo Choi ◽  
Jane P. Chang
Keyword(s):  
Conduction Band ◽  
Photoelectron Spectroscopy ◽  
Density Functional ◽  
Atomic Layer ◽  
Band Alignment ◽  
Functional Theory ◽  
X Ray ◽  
Conduction Band Offset ◽  
Mos Devices ◽  
Layer Deposition

The electronic properties of HfO2 films on 4H-SiC were investigated to determine their suitability as high-κ dielectrics in SiC power MOS devices. The band alignment at the HfO2/4HSiC interface was determined by X-ray photoelectron spectroscopy (XPS) and supported by density functional theory (DFT) calculations. For the experimental study, HfO2 films were deposited on ntype 4H-SiC by atomic layer deposition (ALD). XPS analysis yielded valence and conduction band offsets of 1.69 eV and 0.75 eV, respectively. DFT predictions based on two monoclinic HfO2/4HSiC (0001) structures agree well with this result. The small conduction band offset suggests the potential need for further interface engineering and/or a buffer layer to minimize electron injection into the gate oxide.

Impact of Interface Defect Passivation on Conduction Band Offset at SiO2/4H-SiC Interface

2012 ◽  
Vol 717-720 ◽  
pp. 721-724 ◽  
Author(s):  
Takuji Hosoi ◽  
Takashi Kirino ◽  
Atthawut Chanthaphan ◽  
Yusuke Uenishi ◽  
Daisuke Ikeguchi ◽  
...  
Keyword(s):  
Conduction Band ◽  
Photoelectron Spectroscopy ◽  
Hydrogen Gas ◽  
Band Alignment ◽  
Band Offset ◽  
Partial Recovery ◽  
Conduction Band Offset ◽  
Interface Defect ◽  
Defect Passivation ◽  
Thermally Grown

The change in energy band alignment of thermally grown SiO2/4H-SiC(0001) structures due to an interface defect passivation treatment was investigated by means of synchrotron radiation photoelectron spectroscopy (SR-PES) and electrical characterization. Although both negative fixed charge and interface state density in SiO2/SiC structures were effectively reduced by high-temparature hydrogen gas annealing (FGA), the conduction band offset (ΔEc) at the SiO2/SiC interface was found to be decreased by about 0.1 eV after FGA. In addition, a subsequent vacuum annealing to induce hydrogen desorption from the interface resulted in not only a slight degradation in interface property but also a partial recovery of ΔEc value. These results indicate that the hydrogen passivation of negatively charged defects near the thermally grown SiO2/SiC interface causes the reduction in conduction band offset. Therefore, the tradeoff between interface quality and conduction band offset for thermally grown SiO2/SiC MOS structure needs to be considered for developing SiC MOS devices.

Valence and Conduction Band States of PCBM as Probed by Photoelectron Spectroscopy at Resonant Excitation

2012 ◽  
Vol 2 (1) ◽  
pp. 59-65 ◽  
Author(s):  
Matthias H. Richter ◽  
Daniel Friedrich ◽  
Dieter Schmeißer
Keyword(s):  
Conduction Band ◽  
Photoelectron Spectroscopy ◽  
Resonant Excitation

scholarly journals Velocity Map Imaging VUV Angle-Resolved Photoelectron Spectroscopy of Isolated Silver Sulfide Nanoparticles

2021 ◽  
Author(s):  
Danijela Danilović ◽  
Dusan Bozanic ◽  
Gustavo A. Garcia ◽  
Laurent Nahon ◽  
Una Stamenović ◽  
...  
Keyword(s):  
Valence Band ◽  
Conduction Band ◽  
Photoelectron Spectroscopy ◽  
Minimum Energy ◽  
Aqueous Dispersion ◽  
Silver Sulfide ◽  
Valence Band Maximum ◽  
Maximum Energy ◽  
Velocity Map Imaging ◽  
Silver Sulfide Nanoparticles

Abstract The angle-resolved photoelectron spectroscopy of isolated silver sulfide nanoparticles was carried out by using velocity map imaging technique at the DESIRS beamline of SOLEIL synchrotron facility. The reported spectroscopy results were obtained after interaction of the synchrotron radiation with a polydisperse aerosol produced from aqueous dispersion of silver sulfide particles, approximately 16 nm in diameter. The photoelectron and UV-Vis-NIR absorption spectra were used to estimate the maximum energy of the valance- and the minimum energy of the conduction-band of the nanoparticles. With respect to the vacuum level, the obtained values were found to be 5.5±0.1 eV and 4.5±0.1 eV for the valence band maximum and conduction band minimum, respectively. The dependence of the asymmetry parameter on the electron energy along the silver sulfide valence band showed an onset of inelastic scattering at ~1 eV electron kinetic energy.

Large conduction band offset at SiO2 /β-Ga2 O3 heterojunction determined by X-ray photoelectron spectroscopy

2016 ◽  
Vol 253 (4) ◽  
pp. 623-625 ◽  
Author(s):  
Keita Konishi ◽  
Takafumi Kamimura ◽  
Man Hoi Wong ◽  
Kohei Sasaki ◽  
Akito Kuramata ◽  
...  
Keyword(s):  
Conduction Band ◽  
Photoelectron Spectroscopy ◽  
Band Offset ◽  
X Ray ◽  
Conduction Band Offset

scholarly journals Photocatalytical Properties and Theoretical Analysis of N, Cd-Codoped TiO2Synthesized by Thermal Decomposition Method

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Hongtao Gao ◽  
Bing Lu ◽  
Fangfang Liu ◽  
Yuanyuan Liu ◽  
Xian Zhao
Keyword(s):  
Thermal Decomposition ◽  
Theoretical Analysis ◽  
Valence Band ◽  
Conduction Band ◽  
Photoelectron Spectroscopy ◽  
Decomposition Method ◽  
Density Functional ◽  
X Ray ◽  
Thermal Decomposition Method ◽  
Bet Specific Surface Area

N, Cd-codoped TiO2have been synthesized by thermal decomposition method. The products were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), UV-visible diffuse reflectance spectra (DRS), X-ray photoelectron spectroscopy (XPS), and Brunauer-Emmett-Teller (BET) specific surface area analysis, respectively. The products represented good performance in photocatalytic degradation of methyl orange. The effect of the incorporation of N and Cd on electronic structure and optical properties of TiO2was studied by first-principle calculations on the basis of density functional theory (DFT). The impurity states, introduced by N 2p or Cd 5d, lied between the valence band and the conduction band. Due to dopants, the band gap of N, Cd-codoped TiO2became narrow. The electronic transition from the valence band to conduction band became easy, which could account for the observed photocatalytic performance of N, Cd-codoped TiO2. The theoretical analysis might provide a probable reference for the experimentally element-doped TiO2synthesis.

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