Possible ordered phases in perovskite manganites are investigated the framework of an effective spin Hamiltonian for atomic limit. Using mean-field approximation combined with a group-theoretical consideration, we determine stable orbital and at finite temperatures. It is found that magnetic ordering low-symmetry spatial arrangement stabilized due to mixing interaction between different multipoles. The resulting states discussed by taking into account effect lattice distortion from cubic...

We developed AlGaAs photocathodes with low electron affinity for long negative (NEA) lifetime. achieved 10 times longer NEA lifetime than conventional NEA-GaAs photocathodes. estimated the appropriate superlattice structure small conduction mini band width, high density of state in and splitting energy between heavy- light-hole bands by theoretical calculation. conclude that AlGaAs–GaAs semiconductor is a suitable photocathode not only has acceptable but also fulfills requirements spread...

The dependence of the quantum efficiency (QE) a Cs/O-activated negative-electron-affinity (NEA) state InGaN photocathode on threading dislocation density (TDD) was investigated. photocathodes with different TDDs were grown sapphire and GaN substrates by metal-organic vapor-phase epitaxy (MOVPE). 1 × 109 cm−2 substrate less than 5 106 substrate. After activation NEA surfaces Cs/O, QEs 1.1% 0.91% Despite TDD difference approximately two orders magnitude, comparable. results show that QE is not...

A photocathode electron source using p-type GaN semiconductor with a negative affinity (NEA) surface has been studied for its ability to maintain an extended NEA state. The key technology of photocathodes is the formation electric dipoles by cesium and gallium atoms on surface, which makes it possible photoexcited electrons in conduction band minimum escape into vacuum. This means that order keep energy spread as small possible, excitation photon should be tuned gap energy. However, damaged...

A high quantum efficiency (QE) can be obtained on negative electron affinity (NEA) surfaces. It is well-known that NEA surfaces formed semiconductor materials such as GaAs by the alternating supply of cesium (Cs) and oxygen (O2), which called yo-yo method. While GaN related compounds InGaN are expected to realize an photocathode with a long lifetime, surface reactions between nitride semiconductors completely different respect increasing rate QE induced O2. In addition, processes...

Abstract A thin p-type InGaN with a negative electron affinity (NEA) surface was used to measure the relaxation time of charge limit (SCL) by irradiating rectangular laser beam pulses at changing interval. The film grown metal organic vapor phase epitaxy and NEA activation performed after sample heat cleaned. 13 nC per pulse 10 ms width obtained from photocathode. current decreased exponentially beginning pulse. initial value irradiation As result, SCL estimated through photocathode...

コムギの多収栽培技術の開発を目的に,耐倒伏性品種「さとのそら」を供試し,慣行の基肥重点型の施肥体系に対して,基肥を減らし追肥で窒素を増施用する生育後期重点施肥の効果を2カ年にわたって検証した.その結果,生育後期重点施肥により,茎立期以降の乾物成長量の大きくなる時期にLAIが高まったこと,登熟期後半まで葉色,NARが高く維持されたことでCGRが高く経過し,成熟期の総乾物重が大きくなった.一方で,茎立期の茎数が少なくなったことに加えて,この時期に窒素を増肥したことで,茎間の同化産物および窒素の競合が緩和され,茎の生存率が高まり,穂数が増加するとともに,シンク容量の大きな穂が形成されて1穂粒数も増加したものと考えられた.さらに登熟期後半までNARが高く維持されたことで1000粒重も増加した.以上の乾物成長経過および収量構成要素の形成の結果,生育後期重点施肥により,収量を15~50%増加させることが可能であった.一方で,成熟期が遅れること,外観品質の低下や子実タンパクの過剰,土壌の酸性化の助長などの普及技術化に向けて改善すべき課題も明らかとなった.

We have used surface photo-absorption (SPA) to investigate the formation of negative electron affinity (NEA) surfaces on p-GaAs during Yo-Yo method, under an alternating supply Cs and O 2 . The SPA spectra showed that first step was different from those in following steps. This suggests structure did not change after initial formed, indicating there could be two adsorption sites GaAs surface, which is previously proposed models.

Pulsed electron beams from a photocathode using an InGaN semiconductor have brought selectively scanning technology to microscopes, where the beam irradiation intensity and area can be arbitrarily selected within field of view in SEM images. The p-type crystals grown metalorganic chemical vapor deposition equipment were used as material for source after surface was activated negative affinity state gun under ultrahigh vacuum. produced pulsed with rise fall time 3 ns, consistent structure...

In this study, we generated 25 multielectron beam (MEB) using an InGaN photocathode with a negative electron affinity state irradiating multilaser beam. The uniformity of the MEB and total current were evaluated. A laser was split into beams spatial light modulator. coefficient variation (CV) power 20%. CV quantum efficiency 1.1%. 12%, about 1.2 μA. These results will enhance development MEB-defect inspection photocathode.

A III–V semiconductor with a few monolayers of alkali metals (e.g., Cs) forms negative electron affinity (NEA) surface, for which the vacuum level lies below conduction band minimum base semiconductor. The photocathodes that form an NEA surface (NEA photocathodes) have various advantages, such as low emittance, large current, high spin polarization, and ultrashort pulsed operation. NEA-InGaN photocathode, is sensitive to blue light, has been studied material next-generation robust...

In this paper, the authors describe effectiveness of thermal annealing in vacuum for quantum efficiency (QE) recovery from Cs/O-activated GaN and GaAs photocathodes. The QE photocathodes at 3.4 eV dropped 1.0% to <0.001% upon exposure nitrogen then increased 0.6% annealing. On other hand, 1.42 did not increase after addition, Cs/O activation, sample was exposed normal laboratory air installed an X-ray photoemission spectroscopy system. Upon 330 °C, three key results were confirmed as...

Core-level photoelectron spectroscopy with the combination of synchrotron radiation (SR) and a laser was used for exploring surface-photovoltage (SPV) effect its temporal profiles in GaAs–GaAsP superlattice (SL). It observed that SPV value SL is suppressed as compared bulk GaAs. However, no significant difference found profile between SL. suggested suppression dominantly due to small band bending under thermal equilibrium.

The photocurrent from a semiconductor photocathode with negative-electron affinity surface can be arbitrarily controlled by the excitation laser power. Applying this characteristic to scanning electron microscope allows probe current at any location on sample. A fast time response is required control high speed. This study used an InGaN for pulsed beam generation and investigated its response. 3.8 ns pulse width 8.1 × 103 cm−2 density was observed, rise fall times of were found 1.7 2.0 ns,...

An InGaN photocathode with a negative electron affinity (NEA) surface is suitable for industrial use because of features such as long quantum efficiency lifetime, availability visible laser an excitation light source, and the presence transmission-type structure. The first objective development gun that can be mounted on scanning microscope (SEM) evaluation beam size at emission point, maximum current, transverse energy beam, which are important factors realizing high probe current in SEM....

The development of pulsed electron sources is applied to microscopes or beam lithography and effective in expanding the functions such devices. laser photocathode can generate short electrons with high emittance, emittance be increased by changing cathode substrate from a metal compound semiconductor. Among substrates, nitride-based semiconductors negative affinity (NEA) have good advantages terms vacuum environment lifetime. In present study, we report gun that utilizes photoelectron...

We measured a spin-dependent luminescence from GaAs–GaAsP strained layer superlattice and GaAs substrate to evaluate the spin polarization of conduction band electrons excited by circularly polarized light. The with mixture group-V elements, As P, was considered as suitable spin-polarized electron source because discrepancy valence reported be larger than that band. observed maximum circular polarizations were 68% 15%, respectively. dependence on excitation photon energy well explained...

The dependence of the electron emission current density on excitation power a Cs/O-activated negative affinity (NEA) InGaN photocathode was investigated. NEA-InGaN increased monotonically with in measured range. reached 5.6 × 103 A/cm2 at an 2.6 106 W/cm2. Using thermal energy estimated by comparing simulation and experimental results [D. Sato, H. Shikano, A. Koizumi, T. Nishitani, Y. Honda, Amano, J. Vac. Sci. Technol. B 39, 062209 (2021)], reduced brightness 4 108 A/m2 sr V derived.

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