Scanning Photoelectron Microscopy for the Characterization of Novel Nanomaterials

Chiou, J. W.; Chia-Hao, Chen

doi:10.1002/9783527632282.ch4

Cited by 2 publications

(2 citation statements)

References 123 publications

(119 reference statements)

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“…By synchronized raster scanning the sample relative to the focused soft X-ray, the excited photoelectrons (PE) were collected and analysed by the analyser. The PE intensity of specific core-level line can be converted into a two-dimensional surface chemical state distribution image 27 . SPEM can also be operated in μ-XPS mode to acquire high-resolution PE spectra.…”

Section: Methodsmentioning

confidence: 99%

Determination of band alignment in the single-layer MoS2/WSe2 heterojunction

et al. 2015

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The emergence of two-dimensional electronic materials has stimulated proposals of novel electronic and photonic devices based on the heterostructures of transition metal dichalcogenides. Here we report the determination of band offsets in the heterostructures of transition metal dichalcogenides by using microbeam X-ray photoelectron spectroscopy and scanning tunnelling microscopy/spectroscopy. We determine a type-II alignment between MoS2 and WSe2 with a valence band offset value of 0.83 eV and a conduction band offset of 0.76 eV. First-principles calculations show that in this heterostructure with dissimilar chalcogen atoms, the electronic structures of WSe2 and MoS2 are well retained in their respective layers due to a weak interlayer coupling. Moreover, a valence band offset of 0.94 eV is obtained from density functional theory, consistent with the experimental determination.

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Section: Methodsmentioning

confidence: 99%

Determination of band alignment in the single-layer MoS2/WSe2 heterojunction

et al. 2015

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“…C 1s spectra of graphene sheets were obtained with SPEM at the National Synchrotron Radiation Research Center, Taiwan. Details of the SPEM setup can be found elsewhere. , The energy of incident X-ray was 380 eV, and the X-ray was focused by a Fresnel zone-plate optical system to a diameter of 100 nm. Two-dimensional mapping of photoelectron intensity at various windows of E b was taken simultaneously.…”

Section: Methodsmentioning

confidence: 99%

Core-Level Shift of Graphene with Number of Layers Studied by Microphotoelectron Spectroscopy and Electrostatic Force Microscopy

et al. 2014

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The dependence of C 1s core-level shift (CLS) of graphene on the number of layer (NL) is significant information to derive the coordination-resolved C 1s core-level energy (E 1s ) of carbon allotropes. To observe the variation of CLS of graphene with NL, binding energy and work function of graphene with various NL were examined by scanning photoelectron microscopy/spectroscopy and electrostatic force microscopy. E 1s of grounded graphene decreased as NL increased. The E 1s of single-layer graphene and multilayer graphene (MLG) is 289.42 and 289.13 eV, respectively. Based on the NL-dependent E 1s of graphene, the CLS of C 1s between a free carbon atom and diamond is 0.74 eV, calculated by the bond-order-length-strength correlation theory. The CLS of graphene with NL supported the existence of surface core-level shift (SCLS) on graphite. The magnitude of SCLS in MLG was +0.09 eV. The effective coordination number is 3.68 for bilayer graphene and 4.31 for the surface carbon layer in MLG.

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Scanning Photoelectron Microscopy for the Characterization of Novel Nanomaterials

Cited by 2 publications

References 123 publications

Determination of band alignment in the single-layer MoS2/WSe2 heterojunction

Determination of band alignment in the single-layer MoS2/WSe2 heterojunction

Core-Level Shift of Graphene with Number of Layers Studied by Microphotoelectron Spectroscopy and Electrostatic Force Microscopy

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