X-ray photoelectron spectroscopy studies of Ge epilayers on Si(100)

1992 ◽  
Vol 70 (10-11) ◽  
pp. 799-802 ◽  
Author(s):  
Z. H. Lu ◽  
J.-M. Baribeau ◽  
T. E. Jackman
Keyword(s):  
Valence Band ◽  
Photoelectron Spectroscopy ◽  
High Energy ◽  
Valence Band Maximum ◽  
High Energy Resolution ◽  
Orbit Splitting ◽  
X Ray ◽  
Photoelectron Diffraction ◽  
Spin Orbit Splitting ◽  
Spectroscopy Studies

High-energy resolution X-ray photoelectron spectroscopy, with full width at half maximum of 0.41 eV for the Si 2p and of 0.54 eV for the Ge 3d, has been used to study the valence band offsets of different strained Ge layers grown on Si (100). The fractional volume changes in Ge epilayers have been measured by X-ray photoelectron diffraction and are used to correct the valence band maximum shifts caused by strained-induced spin-orbit splitting at the maxima. Band offset values of 0.80, 0.76, and 0.71 eV are found for Si/(Ge5Si5)/Si (100), Si/(Ge4Si4)/Si (100), and Si/(Ge0.5Si0.5)/Si (100) epilayers, respectively.

Interface Characterization of PbTe/BaSi/Si Heterostructures Grown Using MBE

1992 ◽  
Vol 281 ◽  
Author(s):  
F. Santiago ◽  
D. Woody ◽  
T. K. Chu ◽  
C. A. Huber
Keyword(s):  
Photoelectron Spectroscopy ◽  
High Energy ◽  
Substrate Material ◽  
Interfacial Region ◽  
X Ray ◽  
Interface Characterization ◽  
Spectroscopy Studies ◽  
Molecular Layers ◽  
Similar Growth

ABSTRACTA new substrate material consisting of a buffer layer of a Ba-Si compound was developed by making use of the chemical reaction between BaF2 and Si. This substrate is very promising for the integration of IV-VI semiconductor materials with silicon. PbTe films of excellent quality, as determined by X-ray and Reflected High Energy Electron Diffraction spectra, have been deposited over (111)- and (100)-oriented silicon wafers of 3 inch diameter. These PbTe films are (100)-oriented irrespective of the Si orientation. X-ray photoelectron spectroscopy studies reveal very interesting chemistry at the interface between Ba-Si and Te. They suggest that BaTe may form between PbTe and Ba-Si at their interface. This interfacial region, which is of the order of only a few molecular layers, appears to be critical in the success of the deposition. Thermal cycling showed that the PbTe/BaSi/Si system is mechanically very stable. The possibility of a similar growth mechanism for the deposition of II-VI semiconductors such as CdTe is considered.

scholarly journals XPS studies of the surface of TiO2:Ag nanopowders

2020 ◽  
Vol 11 (4) ◽  
pp. 547-555
Author(s):  
O. M. Korduban ◽  
◽  
T. V. Kryshchuk ◽  
V. O. Kandyba ◽  
V. V. Trachevskii ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Photoelectron Spectroscopy ◽  
Lattice Distortion ◽  
Orbit Splitting ◽  
Xps Spectra ◽  
X Ray ◽  
Annealing Conditions ◽  
Oxide Hydroxide ◽  
Spin Orbit Splitting ◽  
Titanium Wire

n-TiO2 and n-TiO2:Ag nanopowders were synthesized by the method of electric explosion of wires (EEW). The doping of nanopowders took place during the explosion of titanium wire, on the surface of which an Ag2O layer of the appropriate mass was applied. The energy of the explosion was equal to Е = 3.1·Еs, where Es is the energy of sublimation of the metal. Based on the synthesized nanopowders, mesoporous n-TiO2 and n-TiO2:Ag films were formed. The phase composition of the surface of several series of n-TiO2 and n-TiO2:Ag samples under different annealing conditions was studied by X-ray photoelectron spectroscopy. The XPS spectra of the Ti2p- and Ag3d- levels were decomposed by the Gauss-Newton method into interconnected components 2p3/2/2p1/2 and 3d5/2/3d3/2 with parameters DЕ = 5.76 eV; I1/I2 = 0.5 and DЕ = 6.0 eV; I1/I2 = 0.66 to take into account the spin-orbit splitting of the pair respectively. The paper presents histograms of the contributions of the components to the Ti2p- and Ag3d- spectra, which vary depending on the degree of doping and annealing conditions for 4 series of samples. According to XPS data, on the surface of EEW nanopowders TiO2 and TiO2:Ag titanium is represented by Ti3+- and Ti4+- states, silver by Ag0-, Ag1+- and Ag2+- states. In all series of samples, the contribution of the Ti3+- state simultaneously increases with an increase in the absolute Ag content, which is a consequence of the lattice distortion through the formation of a surface phase with Ti–O–Ag bonds. Annealing at 300 °C in air leads to an increase in the contribution to the spectra of Ti4+- states of ЕbTi2p3/2 = 458.3 eV and Ag1+ - states. Pretreatment of the samples with hydrogen peroxide before annealing leads to an increase in the contribution of oxide-hydroxide phases of titanium and Ag0- states. Annealing of the samples at 300 °С in argon with pretreatment with hydrogen peroxide leads to an increase in the contribution to the spectra of Ti4+- states with ЕbTi2p3/2 = 458.8 eV, oxide-hydroxide phases of titanium and Ag0. It has been found that the direction of redox processes on the surface of n-TiO2 after the action of H2O2 and subsequent annealing in air depends on the state of hydration of the original nanopowders.

Spin–orbit splitting in graphene, silicene and germanene: Dependence on buckling

2018 ◽  
Vol 32 (05) ◽  
pp. 1850055 ◽  
Author(s):  
Ranber Singh
Keyword(s):  
Valence Band ◽  
Valence Band Maximum ◽  
Honeycomb Structure ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Orbit Splitting ◽  
Band Maximum ◽  
Honeycomb Structures ◽  
Spin Orbit Splitting

The spin–orbit splitting (E[Formula: see text]) of valence band maximum at the [Formula: see text] point is significantly smaller in 2D planner honeycomb structures of graphene, silicene, germanene and BN than that in the corresponding 3D bulk counterparts. For 2D planner honeycomb structure of SiC, it is almost same as that for 3D bulk cubic SiC. The bandgap which opens at the K and K[Formula: see text] points due to spin–orbit coupling (SOC) is very small in flat honeycomb structures of graphene and silicene, while in germanene it is about 2 meV. The buckling in these structures of graphene, silicene and germanene increases the bandgap opened at the K and K[Formula: see text] points due to SOC quadratically, while the E[Formula: see text] of valence band maximum at the [Formula: see text] point decreases quadratically with an increase in the magnitude of buckling.

Silicon and Germanium Network Polyhedra viewed from Soft X-ray Spectroscopy

2007 ◽  
Vol 1044 ◽  
Author(s):  
Jun Tang ◽  
Takeshi Rachi ◽  
Marcos A Avila ◽  
Toshiro Takabatake ◽  
FagZhum Guo ◽  
...  
Keyword(s):  
Valence Band ◽  
Photoelectron Spectroscopy ◽  
High Performance ◽  
Theoretical Calculations ◽  
High Energy ◽  
Wave Functions ◽  
X Ray ◽  
Atomic Orbitals ◽  
Energy Facility ◽  
Silicon And Germanium

AbstractThe electronic states of Ba8Ga16Ge30 and Sr8Ga16Ge30 are studied by soft x-ray photoelectron spectroscopy (XPS) at a high-energy facility. In Ba8Ga16Ge30, three bands are resolved in the valence band region. Resonance experiments together with theoretical calculations show that the three band structures in the valence band are mainly constructed by the Ge/Ga 4s and 4p wave functions with little contributions of Ba 5s, 5p and 5d. The valence band of Sr8Ga16Ge30 shows a similar feature to that of Ba8Ga16Ge30. It is clearly shown that the atomic orbitals of Ba and Sr make little hybridization with the orbitals made by the framework polyhedra. This provides the understanding of the thermoelectricity in clathrates, and assists the design in high performance thermoelectric materials in this family.

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