Conduction-band electronic structure of 1T-TaS2revealed by angle-resolved inverse-photoemission spectroscopy

2014 ◽  
Vol 89 (15) ◽  
Author(s):  
Hitoshi Sato ◽  
Masashi Arita ◽  
Yuki Utsumi ◽  
Yutaka Mukaegawa ◽  
Minoru Sasaki ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Conduction Band ◽  
Photoemission Spectroscopy ◽  
Inverse Photoemission ◽  
Inverse Photoemission Spectroscopy

Study of Band Alignment at CBD-CdS/Cu(In1-xGax)Se2 (x = 0.2 - 1.0) Interfaces by Photoemission and Inverse Photoemission Spectroscopy

2007 ◽  
Vol 1012 ◽  
Author(s):  
Shimpei Teshima ◽  
Hirotake Kashiwabara ◽  
Keimei Masamoto ◽  
Kazuya Kikunaga ◽  
Kazunori Takeshita ◽  
...  
Keyword(s):  
Band Gap ◽  
Conduction Band ◽  
Valence Band Maximum ◽  
Band Gap Energy ◽  
Band Alignment ◽  
Photoemission Spectroscopy ◽  
Gap Energy ◽  
Conduction Band Offset ◽  
Inverse Photoemission ◽  
Inverse Photoemission Spectroscopy

AbstractDependence of band alignments at interfaces between CdS by chemical bath deposition and Cu(In1-xGax)Se2 by conventional 3-stage co-evaporation on Ga substitution ratio x from 0.2 to 1.0 has been systematically studied by means of photoemission spectroscopy (PES) and inverse photoemission spectroscopy (IPES). For the specimens of the In-rich CIGS, conduction band minimum (CBM) by CIGS was lower than that of CdS. Conduction band offset of them was positive about +0.3 ~ +0.4 eV. Almost flat conduction band alignment was realized at x = 0.4 ~ 0.5. On the other hand, at the interfaces over the Ga-rich CIGS, CBM of CIGS was higher than that of CdS, and CBO became negative. The present study reveals that the decrease of CBO with a rise of x presents over the wide rage of x, which results in the sign change of CBO around 0.4 ~ 0.45. In the Ga-rich interfaces, the minimum of band gap energy, which corresponded to energy spacing between CBM of CdS and valence band maximum of CIGS, was almost identical against the change of band gap energy of CIGS. Additionally, local accumulation of oxygen related impurities was observed at the Ga-rich samples, which might cause the local rise of band edges in central region of the interface.

Modification on the Unoccupied Electronic Structure of Organic Semiconductor by Alkali Metal

2007 ◽  
Vol 1029 ◽  
Author(s):  
Huanjun Ding ◽  
Kiwan Park ◽  
Yongli Gao
Keyword(s):  
Electronic Structure ◽  
Alkali Metal ◽  
Direct Evidence ◽  
Copper Phthalocyanine ◽  
Photoemission Spectroscopy ◽  
Inverse Photoemission ◽  
Lowest Unoccupied Molecular Orbital ◽  
Inverse Photoemission Spectroscopy ◽  
Doping Ratio ◽  
Gap State

AbstractWe have investigated the evolution of both the occupied and unoccupied states for alkali metal (Cs and Na) doped Copper-Phthalocyanine (CuPc) with photoemission and inverse photoemission spectroscopy. As the doping ratio increases, the lowest unoccupied molecular orbital (LUMO) of CuPc shifts downward, reaching the Fermi level. After the saturation, the LUMO intensity decreases monotonically, while a gap state grows in the valence spectra, which gives direct evidence for the origin of the doping-induced gap state in CuPc molecules.

Photoemission Investigation of the Energy Level Alignment at the Rubrene/metal Interface

2007 ◽  
Vol 1029 ◽  
Author(s):  
Huanjun Ding ◽  
Yongli Gao
Keyword(s):  
Electronic Structure ◽  
Energy Level ◽  
Photoemission Spectroscopy ◽  
Strong Interactions ◽  
Metal Interface ◽  
Interface Dipole ◽  
Inverse Photoemission ◽  
Level Shifts ◽  
Lowest Unoccupied Molecular Orbital ◽  
Inverse Photoemission Spectroscopy

AbstractThe electronic structure of the interfaces between rubrene and various metals, including Au, Ag, Al, and Ca, have been investigated with photoemission and inverse photoemission spectroscopy. The formation of the interface dipole is observed at all interfaces. The Fermi level shifts linearly within the band gap as a function of metal workfunction, until it is pinned at the lowest unoccupied molecular orbital (LUMO) by Ca. Strong interactions take place at the interface between rubrene and Ca, evidenced by the evolution of the valence features.

Electronic structure of the prototypical As:Si(111)-1×1 surface investigated by inverse-photoemission spectroscopy

1994 ◽  
Vol 49 (23) ◽  
pp. 16539-16543 ◽  
Author(s):  
S. Bouzidi ◽  
T. Angot ◽  
F. Coletti ◽  
J.-M. Debever ◽  
J.-L. Guyaux ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Photoemission Spectroscopy ◽  
Inverse Photoemission ◽  
Inverse Photoemission Spectroscopy

Electronic Structure of Ionic Liquids Studied by UV Photoemission and Inverse Photoemission Spectroscopy

2006 ◽  
Vol 965 ◽  
Author(s):  
Toshio Nishi ◽  
Yasunori Kamizuru ◽  
Kaname Kanai ◽  
Yukio Ouchi ◽  
Kazuhiko Seki
Keyword(s):  
Electronic Structure ◽  
Ionic Liquids ◽  
Electronic Structures ◽  
Band Gaps ◽  
Photoemission Spectroscopy ◽  
Calculated Density ◽  
Inverse Photoemission ◽  
Ultraviolet Photoemission Spectroscopy ◽  
Inverse Photoemission Spectroscopy ◽  
Highest Occupied Molecular Orbitals

ABSTRACTElectronic structures of the ionic liquids were studied by ultraviolet photoemission spectroscopy (UPS) and inverse photoemission spectroscopy (IPES). The sample materials contain 1-buthyl-3-alkylimidazolium ion [Cnmim]+ (n=4, 8, 10) as the cation in combination with fluorine-containing anions (tetrafluoroboronate BF4−, hexafluorophosphate PF6−). Comparing the calculated density of states with the observed spectra, we found that the ionization thresholds of these ionic liquids are determined by the highest occupied molecular orbitals (HOMO) of the cation, although the calculated HOMOs of the isolated anions are higher than that of isolated cation. The combination of the UPS and IPES results reveals that the band gaps of these ionic liquids are determined by only cation.

Band Bending of n-GaP(001) and p-InP(001) Surfaces with and without Sulfur Treatment Studied by Photoemission (PES) and Inverse Photoemission Spectroscopy (IPES)

2011 ◽  
Vol 222 ◽  
pp. 56-61
Author(s):  
K.Z. Liu ◽  
Masaru Shimomura ◽  
Y. Fukuda
Keyword(s):  
Conduction Band ◽  
Surface States ◽  
Conduction Band Edge ◽  
Photoemission Spectroscopy ◽  
Clean Surface ◽  
Dangling Bond ◽  
Xps Spectra ◽  
Flat Bands ◽  
Inverse Photoemission ◽  
Inverse Photoemission Spectroscopy

Surface electronic structures of n-GaP(001) and p-InP(001) with and without sulfur treatment have been studied by X-ray photoelectron spectroscopy (XPS), synchrotron radiation photoemission spectroscopy (SRPES), and inverse photoemission spectroscopy (IPES). The Fermi level (EF) of a clean n-GaP(001)-(2x4) surface is found to be pinned at 0.2 eV above the valence band maximum (VBM), suggesting that the surface electronic bands are bent upward. XPS spectra reveal that the EF is moved to 2.3 eV above the VBM by the sulfur treatment, implying that the sulfur-treated surface has flat bands. The IPES result shows that empty dangling bond states on Ga atoms at the surface are located at the conduction band minimum (CBM) and they disappeared with the treatment. SRPES spectra of a clean p-InP(001)-(2x4) surface indicate that the EF is located at 0.3 eV above the VBM and surface states due to phosphorus atoms are at –0.9 eV below the EF. The result implies that the surface has almost flat bands. Empty dangling bond states on In atoms at the clean surface are found to be located at the conduction band edge. Surface states due to the In-S bonds are found at –3.5 eV below the EF for the sulfur-treated surface. The sulfur treatment of the clean surface leads to a little shift (0.1 –0.2 eV) of the EF and to considerable reduction of the empty states in the band gap. A type conversion of p- to n- is not observed in the present work. This is discussed in terms of the thickness of a sulfide layer.

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