Low-energy electron microscopy (LEEM) was used to measure the reflectivity of low-energy electrons from graphitized $\mathrm{SiC}(0001)$. The shows distinct quantized oscillations as a function energy and graphite thickness. Conduction bands in thin films form discrete levels whose wave vectors are normal surface. Resonance incident with these conduction band states enhances transmit through film into $\mathrm{SiC}$ substrate, resulting dips reflectivity. dip positions well explained using...

We used spectroscopic photoemission and low-energy electron microscopy to investigate the electronic properties of epitaxial few-layer graphene grown on 6H-SiC(0001). Photoelectron emission (PEEM) images using secondary electrons (SEs) $\text{C}\text{ }1s$ photoelectrons can discriminate areas with different numbers layers. The SE spectra indicate that work function increases number layers unoccupied states in promote emission. PEEM core level shifts lower binding energies as increases,...

The energetics of the atomic process Si-oxide growth on Si(100) surfaces and at ${\mathrm{SiO}}_{2}$/Si(100) interfaces are theoretically studied by first-principles calculation. It is found that stress induced during plays a crucial role in procedure itself. preferential direction oxide nucleus vertical to substrate, whereas lateral. Moreover, Si atoms inevitably emitted from interface release growth.

A method of calculating momentum matrix elements using pseudopotentials is proposed. core-repair term introduced in the to eliminate errors created by poor representation atomic core region pseudopotentials. Calculating requires fewer computational resources especially for separable form This approach suitable non-norm-conserving as well general norm-conserving The effectiveness verified various isolated atoms. also applied calculate planar polysilane, siloxene, gallium arsenide, and nitride.

The essential role that Si atoms emitted from the interface play in determining silicon-oxidation rate is theoretically pointed out, and a universal theory for oxide growth taking account of interfacial Si-atom emission developed. Our can explain whole range thickness without any empirical modifications, while an less than 10 nm dry oxidation cannot be explained with Deal-Grove theory.

We review our research towards single-crystal growth of epitaxial few-layer graphene (FLG) on SiC substrates. have established a method for evaluating the number layers microscopically using low-energy electron microscopy. Scanning probe microscopy in air is also useful estimating number-of-layers distribution FLG. The dependence work function and C1s binding energy determined photoelectron emission investigate processes FLG basis microscopic observations surface morphology distribution. To...

We used low-energy electron microscopy (LEEM) and scanning tunneling (STM) to investigate domain structures of epitaxial few-layer graphene grown on SiC(0001). Dark-field (DF) LEEM images formed using (10) (01) beams clearly indicate that bilayer consists two types domains, which have threefold symmetry are rotated by $180\ifmmode^\circ\else\textdegree\fi{}$ with respect each other. The DF show clear contrasts at energies where (10)- (01)-beam intensities calculated for bulk graphite largely...

Carrier density and temperature-dependent transport properties of monolayer graphene grown on SiC(0001) were systematically studied. With increasing temperature, resistivity at the charge neutrality point decreases, while away from point, where carrier is above 1 \ifmmode\times\else\texttimes\fi{} 10${}^{11}$ cm${}^{\ensuremath{-}2}$, increases. From Hall measurements temperature dependence conductivity, 2 K estimated to be 10${}^{10}$ cm${}^{\ensuremath{-}2}$ or below. Such low implies a...

High-quality monolayer graphene was grown on the Si face of SiC by thermal decomposition, and its electrical properties were investigated in top-gated devices. At 2 K, carrier mobility exceeded 10,000 cm2 V-1 s-1 half-integer quantum Hall effect observed. The states even observed at various densities when top-gate bias applied. These findings suggest high-quality epitaxial possesses unique nature is robust against device fabrication, which holds potential for graphene-based electronics applications.

The origin of the potential profile in silicon single-electron transistors (SETs) fabricated using pattern-dependent oxidation (PADOX) is investigated by making use geometric structure measured atomic force microscope (AFM), bandgap reduction due to compressive stress generated during PADOX obtained first-principles calculation, and effective method. A probable mechanism for formation responsible SET operation proposed. width wire region produces a tunnel barrier, while lowers bottom...

The epitaxial graphene growth mechanism on SiC(0001) surfaces is studied based the energetics via first-principles calculation. It found that a Si terminated surface important for of thin flat sheets. This encourages sheets because atoms act as catalyst. desorbed sites trap excess C atoms, and form islands. also new sheet prefers to grow just SiC substrate even if covered with other

Self-diffusion coefficients of Si in thermally grown SiO2 on a semiconductor-grade silicon wafer have been determined at temperatures between 1150 and 1300 °C under equilibrium conditions using isotope heterostructures (natSiO2/28SiO2). self-diffusion was induced by appropriate heat treatments, the diffusion depth profiles Si30 from SiO2nat to SiO228 layers were secondary ion mass spectrometry (SIMS). The found present study for 1150–1300 are more than two orders magnitude smaller values...

The nitrogen-doping effect on vacancy aggregation in Si is studied by comparing total energies of various complexes nitrogen atoms and vacancies terms first-principles calculations. Two are found to form a stable complex with two vacancies, strongly suggesting that supersaturation “isolated” growth cooling can be suppressed. delayed void formation observed N-doped Czochralski indeed supports this suggestion.

The submonolayer regime of the thermal (600 \ifmmode^\circ\else\textdegree\fi{}C) oxide growth process on Si(111)7\ifmmode\times\else\texttimes\fi{}7 surfaces has been studied in comparison with room-temperature (RT) oxidation using scanning tunneling microscopy (STM), x-ray photoelectron spectroscopy (XPS), and STM simulation based empirical tight-binding method. measurements show randomly distributed dark or depressed areas oxidized at room temperature 600...

Self-diffusion of Si in thermally grown SiO2 is modeled taking into account the effect SiO molecules generated at Si/SiO2 interface and diffusing to enhance self-diffusion. Based on model, a recent self-diffusion experiment ion-implanted Si30 SiO2, which showed increasing self-diffusivity with decreasing distance between diffusers [Fukatsu et al., Appl. Phys. Lett. 83, 3897 (2003)], was simulated, simulated results fit experimental profiles. Furthermore, simulation predicts that would...

Abstract With the aim of developing a single-crystal graphene substrate indispensable to graphene's practical applications, we are investigating structural and physical properties epitaxially grown on SiC by thermal decomposition. We grow monolayer bilayer uniformly micrometre scale Si face in an Ar environment ultra-high vacuum, respectively. Epitaxial graphene, even if uniform thickness, contains two types domains with different stacking orders. compare transport using top-gate Hall bar...