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We analyzed the surfaces of hydrogen-intercalated graphene on SiC(0001) by photoelectron spectroscopy and Raman spectroscopy after applying electric currents to the graphene for carrier mobility measurements while the sample was exposed to air. We found that Si at the interface between graphene and SiC oxidizes very gradually, whereas the graphene does not. The Si of this Si oxide is mainly divalent, and the oxide is attributed to SiO molecules. These molecules are volatile, and they have not been observed either on the oxidized surface of SiC(0001) or on oxygen-intercalated graphene/SiC(0001) formed by annealing in air or oxygen. This anomalous oxidation, which is triggered by the application of current to the graphene overlayer, could be observed because of the presence of the graphene overlayer and the oxidation at room temperature.

A 70-year-old Japanese man presented at our hospital with an asymptomatic, blackish, irregularly shaped plaque with a gray nodule in the periphery on his left lower leg. The lesion had been present for 10 years and had recently enlarged, associated with bleeding. Histopathologically, the tumor consisted of three distinct parts: The first part showed massive aggregation of basophilic basaloid cells with peripheral palisading and abundant melanin granules, and was diagnosed as solid-type basal cell carcinoma. The second part showed aggregation of clear cells with squamous eddies, and was diagnosed as proliferating trichilemmal tumor. The third part showed reticular aggregation of basaloid cells with infundibular cysts in the papillary dermis, and was diagnosed as infundibulocystic basal cell carcinoma. We diagnosed this tumor as basal cell carcinoma with various forms of hair follicle differentiation, including differentiation into the outer root sheath.

An 8-year-old girl presented with a two-year history of nail changes and alopecia areata on the scalp. Although the alopecia was improved by topical applications of corticosteroids, nail changes developed on all fingers and toes. After six months, all fingers and toes showed redness and swelling; physical examination revealed onycholysis with subungueal debris (figure 1A). Erythematous swelling of the soft tissues of the distal interphalangeal (DIP) joint was evident on all fingers and toes, which [...]

A heating treatment is often used in graphene research to remove adsorbates and resist materials from graphene. Heating graphene followed by air exposure is also known to result in heavy hole doping in graphene, although the role of heating has been unclear. Here, we demonstrate that a practical graphene sample fabricated using the commonly used growth and transfer techniques is unstable against heating in a high vacuum. Structural disorder likely due to defect formation is induced by heating, and the disorder is accompanied by hole doping. Our analysis shows that the main cause of the defect formation is graphene reacting with O2 and H2O molecules inserted between graphene and the substrate. The hole doping caused by air exposure after heating is explained by gas adsorption at the defect sites.

We investigated the growth of graphene by molecular beam epitaxy (MBE) using cracked ethylene as a growth source gas under various growth conditions. The analyses of the C 1 s core-level photoelectron spectra and the D-, G-, and 2D-band peaks in Raman spectra revealed that graphene was successfully grown by MBE when cracked ethylene was used as a source gas. Analyses of surface morphology by atomic force microscopy and the substrate temperature dependence of the grown graphene thicknesses indicated that the graphene growth process is essentially the same as that for ethanol. Furthermore, when graphene was grown under a high vacuum, the flow-rate dependence of the deposition rate of graphitic materials demonstrated the expected trend that the deposition rate increased with increasing flow rate. In addition, we found that use of the ethylene improves the domain size of the MBE graphene and that the high-vacuum growth further enhances it, suggesting that the migration enhancement of the growth materials is the key to improving the quality of the graphene in MBE growth.

We studied the growth of graphene by molecular beam epitaxy (MBE) using ethylene and evaluated the MBE-grown graphene. The flow rate dependence of the carbon deposition rate in the ethylene MBE indicated a gradual decrease of the deposition rate with increasing flow rate. This is an improvement from that deposition rate with ethanol, which abruptly decreases because of an etching effect. This feature of ethylene enhances the condition for the growth of the high-quality graphene. Raman spectroscopy measurement and atomic force microscopy observation show that the quality of graphene grown using ethylene is improved from that grown using ethanol from the viewpoints of a domain size and crystallinity. These results demonstrate the advantages of ethylene over ethanol in the MBE growth of graphene.

To evaluate graphene grown by a new method based on gas-source molecular beam epitaxy (MBE), in which a cracked-ethanol source is employed, from the macroscopic viewpoint, we investigated crystal truncation rod scattering by x-ray reflectivity measurement. From the analysis of the x-ray reflectivity data, we found that the MBE-grown graphene forms a layered atomic structure from the macroscopic view, too. The average spacing of the MBE-grown graphene was 3.39 A, which is larger than the interlayer spacing values for bulk crystalline graphite, and the height distributions of the MBE-grown graphene were relatively large. The occupancies of the graphene are smaller than unity and are smaller than that of its underlying graphene, suggesting that graphene did not grow in a layer-by-layer manner but in a three dimensional one, while each layer grew laterally. These results indicate that our new approach is feasible for the formation of wafer-scale graphene, although further improvement of the quality of the graphene by optimizing the growth condition is needed. [DOI: 10.1380/ejssnt.2011.58]

Eccrine spiradenoma (ES) usually occurs as a solitary small nodule. It presents rarely as multifocal or multiple localized tumors arranged in a linear, zosteriform or nevoid distribution. We present a rare case of a 55-year-old woman who had a 48-year history of multiple vascular eccrine spiradenomas (VES) localized on the left side of the submandibular region and neck. All five tumors were skin-colored or pinkish-purple, and ranged in size 1.5-2.5 cm. Histologically, each tumor was composed of two characteristic cell types and many dilated vascular spaces were noted in the stroma. Contrast-enhanced computed tomography showed irregularly shaped, enhanced areas at the center of the tumors. A published work search revealed 35 cases of multiple ES, but multiple VES was extremely rare. We summarized the features of previously reported multiple ES and discuss the clinical and histological classification of ES.

Hydrogen-terminated diamond surface exhibits p-type conductivity during its exposure to air. To investigate this phenomenon, we examined the influence of different gases on the surface conductivity. Exposure to NO 2 gas resulted in the biggest increase in conductivity, while H 2 O vapor decreased the surface conductivity. Moreover, even very low concentrations of NO 2 molecules in air increased the hole sheet concentration, and with increasing NO 2 concentration, the hole sheet concentration increased up to 2.3 × 10 14 cm − 2 (at 300 ppm NO 2 ). This increase of hole sheet concentration was observed during exposure to NO 2 gas and simultaneous adsorption of NO 2 molecules on the diamond surface, while it decreased when the exposure stopped and NO 2 molecules desorbed from the surface. X-ray photoelectron spectroscopy investigation showed upward band bending and partial oxidation of the hydrogen-terminated surface after exposure to air and NO 2 . FETs exposed to NO 2 gas exhibited lower source and drain resistances, which led to a 1.8-fold increase of maximum drain current, transconductance increased 1.5-fold and maximum frequency of oscillation increased 1.6-fold.

To obtain few-layer graphene (FLG), we propose a new growth process based on gas-source molecular beam epitaxy, in which a cracked-ethanol source is employed. To show the feasibility of this growth process, we tried to homoepitaxially grow FLG on epitaxial graphene formed on a SiC substrate. The results of Raman scattering, transmission electron microscopy, and in situ X-ray photoelectron spectroscopy analyses prove that graphene was formed on the substrate, indicating that our approach is feasible for the formation of wafer-scale FLG.

Overexpression of class III beta-tubulin (TUBB3) is an important mechanism of taxane resistance. Using 7 melanoma cell lines, 2 normal neonatal human epidermal melanocyte (NHEM) cultures, and 49 primary melanomas, we investigated TUBB3 expression, its relationship to chemosensitivity to taxane derivatives, and the epigenetic mechanism controlling TUBB3 gene expression. Normal melanocytes in vitro and in vivo strongly expressed TUBB3 protein. NHEMs exhibited marked chemoresistance to paclitaxel-induced apoptosis. A subset (10 of 49, 20%) of primary malignant melanomas was TUBB3 negative. The incidence of TUBB3-negative melanomas increased with stage of progression. TUBB3 protein expression varied among cell lines; one (HMV-I) of the seven cell lines exhibited an extremely low endogenous level. TUBB3 protein expression correlated well with chemosensitivity to paclitaxel-induced apoptosis (P0.05). Treatment with a histone deacetylase (HDAC) inhibitor restored TUBB3 expression in HMV-I. Chromatin immunoprecipitation assays revealed that histones H3 and H4 were hypoacetylated at the TUBB3 gene in HMV-I as compared with a TUBB3-overexpressing cell type (HMV-II). Treatment with the HDAC inhibitor induced gain of histone acetylation only in HMV-I. These results suggest that loss of TUBB3 protein may be induced by histone deacetylation in a subset of malignant melanomas, and may be associated with chemosensitivity to taxane.

To investigate the effect of the oxide layer on the oxide-mediated growth in solid phase epitaxy for the formation of a single-phase iron disilicides, the annealing processes were analyzed using spectroscopic photoemission and low-energy electron microscopy for a special surface where oxide areas and clean substrate areas (voids) coexist closely in a micrometer-order view. From the analysis of high-resolution X-ray adsorption near edge structure (XANES), we found that a pure α phase of FeSi2 was obtained in the oxide area after annealing at 720 °C, although a mixture of its α and β phases was obtained in the void area. This indicates that the oxide layer effectively worked and a single-phase α-FeSi2 was successfully formed by the oxide-mediated growth. Copyright © 2008 John Wiley & Sons, Ltd.

We used spectroscopic photoemission and low-energy electron microscopy to measure two-dimensional (2D) emission patterns of secondary electrons (SEs) emitted from graphene layers formed on SiC(0 0 0 1). The 2D SE patterns measured at the SE energies of 0–50 eV show energy-dependent intensity distributions in the 6-fold symmetry. The SE patterns exhibit features ascribed to energy band structures of 2D free electrons, which would prove that electrons are partially confined in thin graphene layers even above the vacuum level.

A vacuum ultra-violet beamline for in situ angle-resolved photoemission spectroscopy of MBE-grown high-Tc superconductors at low temperature has been constructed at beamline ABL-6B of the normal-conducting ring in the synchrotron radiation facility of the NTT Atsugi R&D Center. The constant-deviation-angle varied-line-spacing plane grating monochromator covers the energy range of 20–200 eV by using two gratings. A photon flux of the order of 1011s−1 with a resolving power of 2000 or more was achieved in the whole energy range. The endstation is equipped with an angle-resolved photoelectron spectrometer, an rf-stimulated He discharge lamp, a custom-designed sample manipulator for low-temperature measurements and a loadlock system for in situ measurements. Total energy resolution of about 13 meV has been obtained for the photoemission spectrum of the Au Fermi edge, in spite of the bending-magnet light source of a second-generation synchrotron radiation ring.

This report describes a vasculitis and subsequently developing angiodestructive lymphoma in an 11-year-old Japanese-Filipino girl exhibiting mosquito allergy with the background of chronic active Epstein-Barr virus (EBV) infection. She developed necrotic skin ulcer at the site of mosquito bite, and histopathological examination revealed EBV-positive mononuclear cell infiltration throughout the wall of small-sized muscular artery. These EBV-positive lymphoid cells were oligoclonal in Southern blot analysis for EBV terminal repeats. Effectiveness of steroid therapy also supports the nonneoplastic nature. Approximately 1 year later, she developed progressive large skin ulcer without mosquito bites. Microscopically, the angiocentric or angiodestructive pattern of EBV-positive atypical cells supported the diagnosis of extranodal natural killer/T-cell lymphoma. Southern blot analysis revealed the monoclonal neoplastic nature of EBV-positive cells. In contrast to the primary mosquito bite lesion, natural killer/T-cell lymphoma cells exhibited the higher expression of EBV latent membrane protein 1 mRNA and the apparent protein expression detected by immunohistochemistry.

The surface phase transition of GaAs (0 0 1) from the As-rich 2×4 surface to the Ga-rich 4×2 surface and the reverse transition were analyzed in real-time using time-resolved core-level photoelectron spectroscopy incorporating the photoelectron diffraction effect. From the analysis of the time dependence of core-level photoelectron intensities and spectra, we found a large anisotropy in the intensities and spectra caused by the photoelectron diffraction effect. This anisotropy in the intermediate state of the transition from the 2×4 to the 4×2 differs from that of the reverse transition, indicating that the surface phase transition pathways differ.

We describe the behavior of iron and cobalt catalysts on silicon substrates in chemical vapor deposition (CVD) of carbon nanotubes. Nanoparticles of iron and cobalt exhibited a melting point drop in methane ambient. Nanoparticles present after nanotube growth are identified as Fe3C and Co3C, for iron and cobalt, respectively. These findings indicate that a eutectic compound of metal and carbon is formed in the methane ambient, resulting in the phase separation of graphite (nanotubes) as the carbon uptake in the catalyst melt increases. This supports the vapor-liquid-solid mechanism for the nanotube growth by CVD. Iron- or cobalt-silicide formation causes poisoning of the catalysts. However, the coexistence of oxygen due to native oxide on the silicon surface or the metal surface causes formation of a SiO2 base that can prevent silicidation of iron particles.

We describe the development of an equipment which can be employed for examining various surface phenomena in real-time by performing time-resolved core-level photoelectron spectroscopy. We demonstrate this unique capability by examining the desorption of Sb atoms occurring from GaSb(001) as well as Sb/GaAs(001) in the temperature range of 440oC∼580oC, which is the usual growth temperature. The time dependence of core-level photoelectron spectra revealed that the activation energy for Sb desorption varies from 0.7 eV to 2.5 eV due to the difference in local bonding structures. In addition, experiments on alternating growth of GaAs suggest that there are two Ga adsorption sites, the occupation of which is dependent on the Ga coverages. This finding is in agreement with theoretical studies. These results demonstrate the potential of the technique to elucidate the surface process by real-time analysis.

Methylation and demethylation of histone H3 lysine 9 (H3K9) play a role in the transcriptional regulation of several cancer-related genes and are closely associated with malignant tumor behavior. A novel study has recently demonstrated that SETDB1, a member of the H3K9 methyltransferases, accelerates tumor formation significantly in a zebrafish melanoma model. However, the expression of H3K9 methyltransferases including SETDB1 and demethylases has not been systematically examined in samples of human melanoma. Here, we used immunohistochemistry to examine the expression of the H3K9 methyltransferases, EHMT2 and SETDB1, and a H3K9 demethylase, LSD1, in 67 patients with melanoma. Overexpression of EHMT2, SETDB1, and LSD1 was observed in 14 (21%), 38 (57%), and 53 (79%) of the 67 patients, respectively. A significant relationship was observed between overexpression of EHMT2 or SETDB1 and aggressive tumor behavior such as lymph node metastasis and/or distant metastasis (P < 0.05), whereas no significant relationship was evident for LSD1 immunoreactivity. Univariate log-rank tests demonstrated that patients with melanoma overexpressing EHMT2 had a poorer outcome (P < 0.001), whereas overexpression of SETDB1 or LSD1 had no prognostic impact. These results suggest that overexpression of EHMT2 might be a prognostic marker in patients with melanoma.

Due to the S passivation, a modified growth of Co on GaAs(001) has been found. Using reflection high-energy electron diffraction and transmission electron microscopy, we observed the formation of a hcp Co overlayer of approximately 5 nm thickness on S/GaAs(001). In contrast, a similar 5 nm Co film on GaAs(001) shows a bcc structure. The metal-semiconductor interfaces in both systems were found to be different, where Co/S/GaAs(001) showed a relatively more abrupt interface. This epitaxial modification is explained on the basis of the morphology of the initial substrate surface, chemical compositions, the nature of the chemical reaction between adatoms and substrate atoms, and the effect of atomic segregation.

A grazing incidence varied line spacing plane grating monochromator (VLS-PGM) has been designed and installed at the Photon Factory bending magnet beamline, BL-1C. The monochromator is designed to cover 20 to 250 eV with a high resolving power as well as a high photon flux and intended for a high-resolution angle-resolved photoemission study of quantum nano-structures. The resolving power of the beamline is observed to be more than 16,000 at around 65 eV and exceeds 10,000 at all the covered energy ranges of the monochromator with photon flux over 10 9 photons/s which shows that this monochromator reaches the expected design goals.

Ga 3d two-hole states were observed from GaAs(111)A-(2×2), (001)-c(4×4), (001)-(2×4), and (110)-(1×1) surfaces using Ga 3p→4s resonant photoemission spectroscopy. The Slater integrals F 2 and F 4 of the Ga 3d orbitals were determined to be 14.4 and 6.0 from the relative energy positions of multiplet terms 1 G, 1 D, and 3 F. Surface components of the two-hole states were observed in the spectra of the (111)A-(2×2), (001)-(2×4) and (110)-(1×1) surfaces involving Ga atoms at the surface. The intensities of the surface components of the two-hole states were found to be considerably smaller than those of the d 9 states. This is ascribed to the reduced absorption probability of the 3p electrons at the surface caused by surface relaxation.

The alternating growth of GaAs on a (001) surface was analyzed by time-resolved core-level photoelectron spectroscopy (CLPES) and measuring reflection high-energy electron diffraction (RHEED) specular beam intensity. When looking at a Ga supply period, a saturation of Ga coverage was found from the time-dependence of Ga CLPES intensity. The RHEED specular beam intensity decreased even after the saturation coverage of Ga. These results indicate that Ga droplets begin to grow after Ga has been grown laterally. The inflection points of photoelectron intensity change were found at about half a monolayer of Ga supply at a substrate temperature of 560°C. The spectrum analysis of the time-resolved CLPES clarifies that the Ga adsorption site changes at about half a monolayer of Ga supply. These results show the potential of using time-resolved CLPES for the real-time analysis of the growth process.

The Ga 3 d two-hole states were observed from GaAs(001)-c(4×4), -2×4, and (110)-1×1 surfaces using resonant photoemission spectroscopy. Multiplet terms 1 G , 1 D , and 3 F were clearly distinguished at the photon energy around the 3 p absorption threshold. The surface components of the two-hole states were observed in the spectra of the (001)-2×4 and (110)-1×1 surfaces having Ga atoms at the surfaces. The curve-fitting analysis revealed that the intensities of the surface component of the two-hole states were considerably smaller than those of the d 9 states. This is ascribed to the reduced absorption probabilities of the 3 p electrons at the surfaces caused by the surface relaxation.

The surface structural changes occurring on Sb-rich Sb-terminated GaAs(001) was investigated by using reflection high-energy electron diffraction and core-level photoelectron spectroscopy. Another surface reconstruction of $2\ifmmode\times\else\texttimes\fi{}8$ superstructure was found, and the analysis of the core-level photoelectron spectra revealed that more of the Sb atoms on this surface are bonded to Sb atoms than to Ga atoms. This indicates the presence of a local structure of stacking double (or triple) Sb layers in which the Sb atoms in the lowest-layer bond with the underlying Ga atoms and in which the number of Sb atoms in the lowest layer is smaller than the number in the other layer(s).

We succeeded in growing carbon nanotubes in a photoelectron spectroscopy analysis system using thermal chemical vapor deposition and analyzed the chemical states of the Co catalysts by in situ X-ray photoelectron spectroscopy before and after the growth. The carbon nanotubes were grown in an ethanol ambient at about 4×10-2 Torr, a relatively low pressure that was used because we needed to subsequently measure photoelectrons under ultrahigh vacuum. We found that almost all of the Co particles are metallic after the growth. This shows that the metallic state is stable for Co under low-pressure ethanol ambient in our growth condition for carbon nanotubes.

The purpose of this study is to determine factors, including laboratory data, related to the relapse of bronchiolitis obliterans organizing pneumonia (BOOP).Retrospective study.The medical files of Fukuoka University Hospital and Nishi Fukuoka Hospital patients from 1984 to 1996 were reviewed, and 18 cases of BOOP that had been diagnosed using transbronchial or open lung biopsy were selected for evaluation.The 18 cases were put into two groups composed of 7 patients who relapsed and 11 who did not relapse. Their clinical symptoms and laboratory data at first admission, including hemograms, blood chemistry tests, and pulmonary function tests were compared. Patients with or without associated diseases, such as collagen vascular diseases, were compared using the same parameters in order to examine the relationship between the associated diseases and BOOP relapse.The serum levels of total protein and albumin in patients who relapsed were significantly lower than in patients who did not relapse, respectively: 5.8 (range, 4.4 to 6.2) vs 6.3 (range, 4.5 to 6.8) g/dL, p0.05; and 2.9 (range, 2.5 to 3.4) vs 3.7 (range, 2.8 to 4.3) g/dL, p0.01. Levels of serum albumin in BOOP patients with associated diseases, however, were significantly lower than in those without associated diseases, respectively: 2.95 (range, 2.5 to 3.9) vs 3.65 (range, 2.8 to 4.3) mg/dL, p0.05. The fall in serum albumin levels in patients who relapsed, therefore, was probably due to associated diseases. The fact that 5 of 8 patients with associated diseases relapsed but only 2 of 10 without associated diseases relapsed suggests that a relationship exists between associated diseases and the prognosis of BOOP, although this finding was not statistically significant because of the small number of cases and the heterogeneity of the associated diseases. The most striking observation was that PaO2 levels in patients who relapsed were significantly lower than in those who did not, respectively: 55.4 (range, 39.9 to 73.2) vs 78.0 (range, 48.4 to 89.4) mm Hg, p0.05. However, PaO2 levels were not statistically different between patients with and without associated diseases, respectively: 66.0 (range, 45.4 to 78.8) vs 71.4 (range, 39.9 to 89.4) mm Hg.The severity of hypoxemia at first medical examination may be an important determinant for the subsequent BOOP relapse.

We have developed a submicron-area high energy resolution photoelectron spectroscopy system equipped with a multilayer-coated Schwarzschild objective for forming a soft x-ray microbeam. We show the photoelectron microspectroscopy results of the cross section of a semiconductor double heterostructure sample, namely an epitaxial film [InP (50 nm thick)/ In0.53Ga0.47As (2.3 μm thick)/InP (100) substrate] grown by metalorganic chemical vapor deposition. The core-level photoelectron spectra were obtained from the cross section of the cleaved sample. The As 3d, Ga 3d, and In 4d peaks were observed in the In0.53Ga0.47As region. In the InP region, the As 3d and Ga 3d peaks were not observed, and only the In 4d peak was. This result corresponds to the structure observed by cross-sectional scanning electron microscopy. Moreover, we observed an irradiation effect that was caused by the microbeam. These results suggest that this photoelectron microspectroscopy system is a powerful tool for studying chemical and electronic states of submicron-area surfaces.

The effects of crystal defects near the surface on the position of surface Fermi level (EFS) are investigated using photoluminescence (PL) measurements and synchrotron radiation photoelectron spectroscopy (SRPES). For the lightly Si-doped GaAs(001) surface, PL measurements reveal that after heating to 500 °C a layer with lower PL peak intensities related to gallium vacancies than those of the bulk exists just under the thermal degraded layer. SRPES shows that EFS moves upward to 1.1–1.17 eV above the valence band maximum when this thermal degraded layer is removed by chemical etching and the excess arsenic on the surface, which is formed by rinsing the etched surface with deoxygenated and deionized water, is evaporated by heating in ultrahigh vacuum (UHV). After evaporation of excess arsenic on the surface by heating, the etching-depth dependence of EFS for a sample preheated in UHV correlated with the existence of this defect concentration layer. These results suggest that the position of EFS for the GaA...

The alternating growth process of GaSb on a (001) surface was analyzed by real-time core-level photoelectron spectroscopy. Using intensity analysis at the Ga supply stage, Ga growth mode was found to change from 2D growth to 3D growth at substrate temperatures between 495 and 520°C. Using intensity analysis at the Sb desorption stage, we found that the behavior of Sb atoms also changed at this temperature. These results show that a substrate temperature of about 500°C is critical for the alternating growth of GaSb(001).

The effects of crystal defects near the surface on the position of surface Fermi level (EFS) are investigated using photoluminescence (PL) measurements and synchrotron radiation photoelectron spectroscopy (SRPES). For the lightly Sidoped GaAs (001) surface, PL measurements reveal that after heating to 500°C a layer with lower PL peak intensities related to gallium vacancies than those of the bulk exists just under the thermal degraded layer. SRPES shows that EFS moves upward to 1.1-1.17 eV above the valence band maximum when this thermal degraded layer is removed by chemical etching. The excess arsenic on the surface, which is formed by rinsing the etched surface with deoxygenated and deionized water, is evaporated by heating in ultra-high vacuum (UHV). After evaporation of excess arsenic on the surface by heating, the etching-depth dependence of EFS for a sample pre-heated in UHV correlates with the existence of this defect concentration layer. These results suggest that the position of EFS for GaAs (001) surface is strongly influenced by crystal defects near the surface.

The interface structure of hydrogen-intercalated graphene/SiC(0001), formed by annealing SiC substrates with the buffer layer at high temperature under atmospheric molecular hydrogen, was investigated by core-level photoelectron spectroscopy. The investigation of C 1s spectra, captured before and after the annealing at various temperatures in a vacuum, indicates that residual materials (hydrocarbon and hydrogen) stayed at the interface on the as-treated sample and remained there until annealing at around 700 ◦ C. These residual materials would cause distortion of the graphene. The analysis of Si 2p photoelectron spectra reveals insufficient termination of Si-dangling bonds at the interface by hydrogen and that significant interface states remained. The interface states of Si dangling bonds are plausible origins of Fermi level pinning and would act as charged impurities. These distortion and charged impurities should degrade the electronic performance of graphene in this system.

Angle-integrated and angle-resolved (AR) photoelectron spectroscopy (PES) experiments were performed on GaAs(001) 2 × 4-Sb surfaces. The results of angle-integrated PES show that only Sb atoms lie on the GaAs surface and that they bond to Ga atoms. ARPES experiments revealed a surface state whose dispersion is very similar to the As dimer dangling bond surface state of As-terminated GaAs(001). These results suggested that Sb dimers terminate GaAs surfaces and bond to Ga atoms of the second top atomic layer.

Various reconstructed GaSb(001) surfaces were prepared and investigated in situ using core-level photoelectron spectroscopy. The change in the surface components of the Ga 3 d and Sb 4 d revealed that Ga atom rows are not necessary for formation of the c(2×6) surface. A new model is proposed in which the origin of the x3 periodicity along the [−110] direction is due to Sb-dimer rows. Another is proposed for the changing of the surface structure from a c(2×6) surface to a Ga-rich 2×3 surface; this model accounts for the appearance of a surface component in the Ga 3 d corresponding to the Ga atom rows under Ga-rich conditions.

We realized 1–4 monolayer MoSe2 films on Se-terminated GaAs (111)B 2-in. substrates by molecular beam epitaxy. Atomically flat GaAs wafers were prepared by the migration-enhanced epitaxy method, and MoSe2 layers were successfully grown on Se-terminated GaAs (111)B surfaces with layer-number control over the entire wafer area. The obtained MoSe2 crystal is well aligned on the GaAs (111)B surface. The quasi-van der Waals gap formed between a Se-terminated GaAs (111)B surface and MoSe2 was directly observed with a scanning transmission electron microscope. All A1g Raman peaks from 93 points on 2-in. monolayer MoSe2 are distributed within 0.25 cm−1, indicating excellent spatial uniformity.