Topic
Photoemission spectroscopy
About: Photoemission spectroscopy is a research topic. Over the lifetime, 10821 publications have been published within this topic receiving 250888 citations. The topic is also known as: photoelectron spectroscopy & PES.
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TL;DR: In this article, the valence and conduction-band discontinuities of InAs-GaAs (100) heterojunctions were determined by means of XPS measurements.
Abstract: The valence‐ and conduction‐band discontinuities have been determined for the InAs–GaAs (100) heterojunction (HJ) by means of XPS measurements. The values are ΔEv = 0.17±0.07 eV and ΔEc = 0.90±0.07 eV, respectively. The InAs‐GaAs HJ has a rather large lattice mismatch (7%) but high quality epitaxial heterojunctions may be grown by molecular beam epitaxy (MBE). We have carried out XPS measurements on MBE grown InAs (100) films and on the InAs‐GaAs (100) HJ by using a recently developed arsenic cap transfer technique which permits XPS measurements on atomically clean and ordered heterojunctions. XPS is used to obtain the In4d and As3d to valence‐band maximum binding‐energy differences for bulk InAs by fitting the experimental XPS valence‐band density of states (VBDOS) to an instrumentally broadened theoretical VBDOS. The values are (EInAsIn4d−EInAsv) = 17.43 ±0.02 eV and (EInAsAs3d−EInAsv) = 40.77±0.02 eV, respectively. The core‐level separation ΔECL between the In4d and Ga3d core levels for a thin InAs–GaA...
82 citations
TL;DR: A synthesis process of WS2 nanosheets with layer controllability and high uniformity using chemical vapor deposition (CVD) and WCl6 and H2S as gas-phase precursors is described and the fabrication and performance of a photodetector based on a hybrid structure consisting of graphene and a WS1 nanosheet is demonstrated.
Abstract: The synthesis of layered transition-metal-disulfide (MS2, M = Mo, W) nanosheets with layer controllability and large-area uniformity is an essential requirement for their application in electronic and optical devices. In this report, we describe a synthesis process of WS2 nanosheets with layer controllability and high uniformity using chemical vapor deposition (CVD) and WCl6 and H2S as gas-phase precursors. Through this process, we can systematically modulate the thickness of WS2 nanosheets by controlling the duration of the reaction between WCl6 and H2S. The CVD-grown WS2 nanosheets exhibit good stoichiometry as well as dependencies of a clear Raman shift and bandgap on the number of layers. These properties are confirmed by X-ray photoemission spectroscopy, Raman spectroscopy, and photoluminescence measurements. The number of layers of WS2 nanosheets is confirmed by atomic force microscopy. Finally, we demonstrate the fabrication and performance of a photodetector based on a hybrid structure consisting of graphene and a WS2 nanosheet.
81 citations
TL;DR: A comparison of the electronic states with a band-noninverted superconductor possessing a similar Fermi surface structure suggests that the anomalous behavior in the superconducting state of Sn(1-x)In(x)Te is related to the peculiar orbital characteristics of the bulk valence band and/or the presence of a topological surface state.
Abstract: We have performed angle-resolved photoemission spectroscopy on the strongly spin-orbit coupled low-carrier density superconductor Sn(1-x)In(x)Te (x = 0.045) to elucidate the electronic states relevant to the possible occurrence of topological superconductivity, as recently reported for this compound based on point-contact spectroscopy. The obtained energy-band structure reveals a small holelike Fermi surface centered at the L point of the bulk Brillouin zone, together with a signature of a topological surface state, indicating that this material is a doped topological crystalline insulator characterized by band inversion and mirror symmetry. A comparison of the electronic states with a band-noninverted superconductor possessing a similar Fermi surface structure, Pb(1-x)Tl(x)Te, suggests that the anomalous behavior in the superconducting state of Sn(1-x)In(x)Te is related to the peculiar orbital characteristics of the bulk valence band and/or the presence of a topological surface state.
81 citations
TL;DR: A spin-glass-type magnetic behavior is also indicated for the ordered ferromagnetic double perovskite La2CoMnO6 based on time-dependent measurements as mentioned in this paper.
Abstract: Epitaxial thin films of the ordered ferromagnetic double perovskite La2CoMnO6 have been grown on (001)-oriented SrTiO3 substrates by pulsed laser deposition. X-ray photoemission spectroscopy analysis suggests that the Mn and Co ions are primarily in the 4+ and 2+ valence states. Magnetic measurements indicate the presence of two phases: a majority and a minority ferromagnetic phase with transition temperatures of 230 and 80K, respectively. A spin-glass-type magnetic behavior is also indicated for the films based on time-dependent measurements. The spin-glass behavior likely arises from a competition between ferromagnetic and antiferromagnetic interactions because of local disorder, even in films grown under optimal conditions.
81 citations