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Amorphous perfluoroalkenyl vinyl ether polymer devices can store a remarkably powerful electric charge because their surface contains nanometre-sized cavities that are sensitive to the so-called quantum-size effect. With a work function of approximately 10 eV, the devices show a near-vertical line in the Nyquist diagram and a horizontal line near the −90° phase angle in the Bode diagram. Moreover, they have an integrated effect on the surface area for constant current discharging. This effect can be explained by the distributed constant electric circuit with a parallel assembly of nanometre-sized capacitors on a highly insulating polymer. The device can illuminate a red LED light for 3 ms after charging it with 1 mA at 10 V. Further gains might be attained by integrating polymer sheets with a micro-electro mechanical system.

High-temperature scanning tunneling microscopy (HTSTM) has been applied to analyze the mechanism of a reversible phase transition between the ‘16×2’ structure and the 1×1 structure appearing on a clean Si(110) surface. The ‘16×2’ structure is the dominant structure on the clean Si(110) surface at room temperature. It has also been shown that the (17,15,1)2×1 steps, whose length is 5 nm in the 〈111〉 direction, exist in the domain of the ‘16×2’ structure. The transition ‘16×2’+(17,15,1)2×1 step⇔(17,15,1)2×1⇔1×1 is observed upon heating, where the first process starts at 968 K and the second finishes at 1043 K. The temperature width between the phase transition is about 80 K. From taking account of the two processes of the transitions, we can say that the system undergoes at first the Ising transition and, at a higher temperature, a roughening transition. Namely, Tc (=968 K) is the temperature for the Ising transition and TR (=1043 K) is that for the roughening transition.

The structure of a Si(001) surface with monatomic steps is investigated by means of scanning tunneling microscopy at 95 K and Monte Carlo simulations (MCS) at various temperatures. In particular, we pay attention to the effect of kinks at the step edge on the formation of c (4×2) domains, and both studies reveal that the kinks do not govern the growth of the domains. MCS demonstrates that the nucleation of c (4×2) domains takes place at central regions of the terrace as a result of thermal fluctuation, and that the domains propagate to the step edge with decreasing temperature.

Indium adsorption and desorption processes on Si(l 11) surfaces were observed in situ by UHV high-temperature STM. By the deposition of In on the Si(111)7 X 7 surfaces at 380°C, the surface structure changed successively to √3 x √3, √31 X √31 and 4 X 1. The number densities of silicon atoms in the restructuring layers for the √3 X √3, √31 X √31, and 4 X I structures were evaluated to be about 0, 1 and 2 ML, respectively. High-resolution STM images were also taken after the deposition.

We carried out STM observations of Si(5 5 12) surfaces. STM images showed that the surface has a long period of about 5 nm along the 〈665〉 direction that coincides with a period of the bulk terminated structure, and a period of about 0.7 nm along the 〈110〉 direction that coincides with a 2-fold period of the bulk terminated structure; the 2 × 1 structure. The long period along the 〈665〉 direction is composed of 7 arrays of bright dots. These bright dots appear at the adatom positions of a surface structure model of the (5 5 12) surface proposed previously from RHEED pattern analysis. The phase shifts of the long period which are equivalent to steps are observed on the surface. A surface structural phase transition found in REM-RHEED studies at about 900°C was also observed.

The structure of kinks at monatomic steps on Si(001) and Ge(001) is investigated by high-resolution scanning tunneling microscopy at room temperature. In addition to previously known asymmetric-dimers at edges of the ${\mathit{S}}_{\mathit{A}}$ and ${\mathit{S}}_{\mathit{B}}$ steps running parallel and perpendicular to dimer rows in the upper terrace, respectively, we have found that kinks at both ${\mathit{S}}_{\mathit{A}}$ and ${\mathit{S}}_{\mathit{B}}$ steps induce buckled (asymmetric-appearing) dimers locally in the connecting dimer rows in the lower terrace. Influence of the kinks on the formation of a c(4\ifmmode\times\else\texttimes\fi{}2) phase of asymmetric dimers at low temperatures is discussed. \textcopyright{} 1996 The American Physical Society.

We have investigated detailed structures of monatomic steps on Ge(001) at room temperature by using high-resolution scanning tunneling microscopy. Our conclusions are different from those of Kersten et al. [Surf. Sci. 322 (1995) 1] for the same system. The most crucial difference is that we have not observed the nonbonded SB step. We have pointed out a possible reason for the different conclusions.

High‐temperature scanning tunneling microscopy was used to study the crystal growth of a (15,17,1) vicinal plane on a Si(110) surface, and the dynamic behavior of surface Si atoms at high temperature was directly observed. It was found that an impurity hillock, which may be SiC on the surface, pins step flows and bunches them together to form a vicinal plane such as (17,15,1), (17,15,1), (15,17,1), and (15,17,1) at 710 °C. The vicinal plane has a faceted structure and is formed by a periodic arrangement of monolayer steps and has a terrace of 2.5 nm in the 〈111〉 direction. The step‐edge direction is 〈112〉. At 695 °C, it was also found that the 16 structure was formed on a flat area. It was confirmed that the 16 structure and the vicinal plane (15,17,1) coexisted in a temperature range of about 700 °C to room temperature.

Scanning tunneling microscopy is used to study the structure of Al-√3×√3domains on the Si(111)-7×7 surface and the atomic arrangement around the domain boundary. Al-√3×√3 domains grow from kink sites of the or step and extend over the Si-7×7 terrace. Detailed investigation around the boundaries reveals that faulted sites face the boundaries on the Si-7×7 side, while on the Al-√3×√3 side, Al adatoms occupy the T 4 sites except on the rows adjacent to the phase boundaries where Al (or Si) atoms are adsorbed on the Si adatom sites. The latter atoms play an important role in retaining the dimer structure at the boundaries

The structure of a GaAs (001) surface is studied by scanning tunneling microscopy at high sample temperatures up to 500°C. Below 460°C, a stable missing dimer row structure is clearly observed. At 480°C, however, the observed structures become disordered and change shape from image to image. This indicates that the thermal motion causes the migration of surface atoms as well as the desorption from the surface at this sample temperature.

In this paper we discuss three experiments on silicon (100) and (111) surface at high temperature obtained with an ultra-high-vacuum scanning tunneling microscope (UHV-STM). First, the initial stage of the crystalization process has directly been investigated on the Si(111) surface at a phase transition temperature of about 860°C. (7 × 7) domains nucleated from the step edges and expanded towards inner regions of the terraces, and the steps become straight [ 1 ¯ 1 ¯ 2 ] steps. Second, the high-temperature nano-fabrication method has been applied to Si surfaces. We succeeded in creating a hexagonal pyramid and a crater on the Si(111) surface, and a quadrangular pyramid on the Si(100) surface at 600°C. (5 × 5) domains can be observed on narrow terraces due to the relaxation of surface energy. Finally, we attempted to deposit gold (Au) atoms on silicon surfaces. Au atoms deposited on a high-temperature silicon surface migrated to the observation area while forming 5 × 1 structures. Then the Au atoms diffused into the bulk structure of silicon, and silicon (7 × 7) domains covered the surface again.

Scanning tunneling microscopy (STM) is used to investigate the surface morphology of Ar+‐ion bombarded Si(001) surfaces and to elucidate the very beginning stages of solid phase epitaxy (SPE) processes of the Ar+‐ion bombarded Si surfaces. The Ar+‐ion bombarded Si surface consists of hillocks of 1–2 nm in diameter and 0.35–0.75 nm in height. The onset of SPE initiates at around 590 °C, at which a temperature (2×2) structure surrounded by amorphous regions is partially observed on terraces of the surface. During annealing at 590–620 °C, the areas of the (2×2) and c(4×4) reconstruction surrounded by amorphous regions develop. New defect models for the (2×2) and c(4×4) structures are proposed where alternating arrangements of the buckled dimers together with missing dimer defects are considered.

The Ga/Si(100) surface is investigated using scanning tunneling microscopy (STM), scanning tunneling spectroscopy (STS), and low-energy electron diffraction. Two distinct peaks are observed on the 2\ifmmode\times\else\texttimes\fi{}2 Ga phase using STS, which are associated with one Ga unoccupied state and two Ga-Si occupied states, respectively. The latter peak is assigned to surface state bands observed using angle-resolved photoelectron spectroscopy [Surf. Sci. 242, 277 (1991)]. Regular arrays of Ga clusters are observed in STM images for the 8\ifmmode\times\else\texttimes\fi{}1-Ga phase. The spacing between Ga cluster arrays is constant, whereas the spacing between the clusters along an array fluctuates. Adjacent arrays are out of phase in the direction perpendicular to the arrays. Steps are severely deformed by the formation of the 8\ifmmode\times\else\texttimes\fi{}1-Ga phase. The initial stage and second-layer growths of the 8\ifmmode\times\else\texttimes\fi{}1-Ga phase are observed. Ga clusters disrupt the 2\ifmmode\times\else\texttimes\fi{}2-Ga phase. \textcopyright{} 1996 The American Physical Society.

We have investigated the transitions that take place at high-temperature from the oxidized state to the 7×7 phase on the Si (111) surface using high-temperature (HT) scanning tunneling microscopy (STM). The oxidized surface was transformed at 580 °C after oxidation by exposing the surface to 45 L of oxygen at 480° C The structural modification was directly observed by HT-STM. The corner adatom was created at the initial stage of the reconstruction, and then the disordered, 5×5 and 7×7 phases successively appeared on the surface. By etching Si atoms, the island structure was formed on the surface because of the reduced Si density. Finally, the completed 7×7 terrace was created.

The surface of the a-7×7 phase of Al/Si(111), which appears at low temperatures with low coverage, is examined by scanning tunneling microscopy. The surface is of 7×7 periodicity based on the DAS (dimer-adatom-stacking fault) structure. Al atoms adsorb as clusters preferentially on the center part of the half unit cells in the DAS model, producing characteristic triangular protrusions. The cluster consists of three Al atoms with each Al atom being bonded to the nearest center adatom. Consequently, the number of the dangling bonds is reduced, which lowers the surface energy. Bias-dependent images reveal that the electronic structure of the center adatoms is modified to be nonmetalliclike because of the saturation of the dangling bonds

Scanning tunneling microscopy (STM) is used to study the structure of Al-√3×√3 domains on the Si(lll)-7×7 surface and the atomic arrangement near the domain boundary. Al-√3×√3 domains grow from the lower side of the <112> step and extend over the Si-7×7 terrace. The phase transition is observed to occur in units of the 7×7 size. Detailed investigation at around the boundary reveals that faulted halves of the 7×7 unit are adjacent to the boundary on the Si-7×7 side, while on the Al-√3×√3 side, Al adatoms occupy the T4 sites except for the rows adjacent to the phase boundaries where Al atoms occupy the Si adatom sites. The latter Al atoms play an important role to retain the dimer structure at the boundary.

Scanning tunneling microscopy (STM) is used to investigate the surface morphology of Ar+-ion bombarded Si(100) surfaces and to elucidate the very beginning stages of solid phase epitaxy (SPE) processes of the Ar+-ion bombarded Si surfaces. The Ar+-ion bombarded Si surface consists of hillocks of 1–2 nm in diameter and 0.35–0.75 nm in height. The onset of SPE initiates at around 590°C, at which temperature a (2×2) structure surrounded by amorphous regions is partially observed on terraces of the surface. During annealing at 590–620°C, the areas of the c(2×2) and c(4×4) reconstruction surrounded by amorphous regions develops. New defect models for the (2×2) and c(4×4) structures are proposed w here alternating arrangements of the buckled dimers together with missing dimer defects are considered. On the other hand, after thermal annealing of the Ar+-ion bombarded Si at 830°C for 10 sec, terraces of (2×1) and (1×2) orientations arc observed on the surface, and pyramidal structures on a nanometer-scale which consists of double-layer step edges (dimer rows perpendicular to terrace edge) arc observed.

The atomic arrangements of the α-7×7 phase and incommensurate phases of Al adsorbed Si(111) surface are investigated respectively by scanning tunneling microscopy (STM). STM images of α-7×7 surface reveal that characteristic triangular structures consisting of three Al adatoms situated on the center part of each half unit cell. The three Al adatoms form a triangular cluster and are bonded to the center adatoms. In this situation, the dangling bond of the center adatom is saturated, which would modify its electronic structure into non-metallic. The incommensurate phase is consists of approximately 9×9 structures, which are separated each other with misfit dislocations. In the “9×9” structure, individual Al atom is visible arranged in threefold symmetry.

High-temperature scanning tunneling microscopy is used to study the statistical distribution of terrace width on an Si(110) surface at 720° C. It is confirmed that the terrace width is fitted by the Gaussian distribution, standard deviations (σ) of which are proportional to the mean terrace width. It is considered that the step-step interaction potential energy is A x -2 (x: normal distance to the step edge and A: proportionality constant). As the mean value of the main peak is 19.27 nm and the step height 0.19 nm, it is confirmed that the surface is oriented within 1° from the (110) surface.

The surface morphology of Ar+-ion-bombarded Si(001) surfaces and its regrowth processes during thermal annealing are studied “in situ” using a scanning tunneling microscope (STM). The amorphous layer consists of grains 0.63∼1.6 nm in diameter. The grains gradually coalesce and forms clusters 2∼3.6 nm in diameter at the annealing temperature of 245°C. The (2×1) and (1×2) reconstructed regions surrounded by amorphous regions are partially observed on the surface after prolonged annealing, which suggests the onset of solid phase epitaxy (SPE). Real-time observation reveals that the smoothing of the surface occurs layer by layer. As the annealing temperature is raised to 445°C, the amorphous layer epitaxially crystallizes up to the topmost surface, and the (2×1) reconstructed surface with monatomic-height steps is observed.

Bi-adsorbed Si(110) surfaces are investigated by scanning tunneling microscopy (STM). The 2×3 structures where two protrusions are observed in a unit cell at the positive and negative sample bias voltages are formed at 700 K. The up and down terraces of the clean 16×2 structure still remain when Bi atoms are deposited at room temperature, while a rather flat surface with boundaries parallel to [-1, 1, 2] (or [1, -1, 2]) is formed by the adsorption of Bi at 570 K. The 2×3 structures of short-range order are also formed on the flat surface at 570 K.

High-temperature scanning tunneling microscopy (HTSTM) was applied to observe a facet structure on a Si(110) surface. The facet structures of (15, 17, 1) and (17, 15, 1) and the 16-structure were observed at 655°C. The 16-structure was formed on flat parts. It was confirmed that the 16-structure and the facet structures of (15, 17, 1) and (17, 15, 1) coexisted on the surface on which hillocks are dispersed. The hillock may be a contamination.

High-temperature scanning tunneling microscopy (HTSTM) has been developed which enables distortionless observation of the dynamic behavior of surface atoms at high temperatures up to 900°C on an atomic scale, and it was applied to analyze the mechanism of reversible phase transition between the 16-structure and the 1x1 structure appearing on a clean Si(110) surface. It has been found that, at first, the reconstruction and destruction of the 16-structure begin on the unit-cell level along the direction and then progress along the direction as a whole in order to complete the phase transition. The direct observation of the reconstruction at high temperatures is very important to investigate the mechanism of crystal growth.