摘要:

Shake‐off of micron‐sized alumina particles by nanosecond laser‐generated surface acoustic wave (SAW) pulses is used to visualize SAW beam propagation on surfaces of semiconductor crystals. Various phenomena in SAW propagation such as reflection from a sample edge, anisotropic diffraction, and beam steering are demonstrated. ©1995 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.359128

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Study of the growth of ultrathin (≤100 A˚) silicon dioxide (SiO2) films by thermal pyrolysis of tetraethoxysilane (TEOS) has been conducted. The oxide growth follows a first‐order or near first‐order relationship with respect to partial pressure of TEOS. The reaction appears to proceed via heterogeneous decomposition with byproduct inhibition with no incubation period. An extremely slow growth process has been investigated for depositing the SiO2film with monolayer thickness control, which is considered to be a critical requirement for forming ultra‐large‐scale integrated devices. ©1995 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.359589

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The effects of hydrogenation on GaAlAs layer grown by molecular beam epitaxy stored over a long period of time was investigated using photoluminescence (PL) measurement. Upon hydrogenation, the defects in the GaAlAs are passivated and the PL intensity increased many times. Hydrogenation changes the energy of the defect produced on storage of GaAlAs and new features appear in excitonic emissions. On annealing the hydrogenated GaAlAs at temperatures ≳500 °C, the defects are depassivated and the PL intensity degraded. Hydrogenation improves the PL intensity of emission from a stack of GaAs/GaAlAs quantum wells (QW) of different well widths by a factor which varies with the depth of the QW from the surface. ©1995 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.359129

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

GaAs microtip for scanning tunneling microscope was fabricated by selective metalorganic chemical vapor deposition. The GaAs tip was constructed by two {111}Bgrowth facets and a cleaved (110) surface. The surface of the GaAs tip was treated by ammonium sulfide solution, and highly oriented pyrolytic graphite surfaces were observed by using the GaAs tip in air. As the result, imagings of the atomic arrangement could be successfully obtained. ©1995 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.359130

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Based on Phillips’ electronegativity theory [Rev. Mod. Phys.42, 317 (1970)] we have determined the alloy scattering potential for the ternary nitrides, Ga1−xAlxN, In1−xGaxN, and In1−xAlxN, and hence the 300 and 77 K electron mobilities through a variational principle calculation. Alloy scattering is important in In1−xGaxN, and In1−xAlxN, both of which show a significant composition ‘‘bowing’’ in electron drift mobility, even at 300 K. This contribution is not important in Ga1−xAlxN. Acoustic phonon scattering is also significant at 300 K, in contrast to the situation obtained in GaAs‐based ternaries. ©1995 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.359131

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

A doubleS‐type instability in an original semiconductorn+/n‐GaAs/i‐AlGaAs/i‐GaAs/p+heterostructure is investigated theoretically by a Monte Carlo simulation. The mechanism responsible for the second instability is the hot‐electron current which, besides itself being a source of anS‐type instability, drives a hot‐hole current whose sharp switching‐on provokes a sudden increase of the heterostructure conductance. An oscillatory behavior of the voltage drop between the heterostructure contacts is predicted. The maximum frequency of the generation so obtained is found to increase from 100 to 500 GHz when the temperature is lowered from 300 to 4 K. ©1995 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.359132

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Tungsten thin films, 200 nm thick, have been chemically vapor deposited by pyrolysis of W(CO)6on oxidized silicon substrates at atmospheric pressure and temperatures varying from 350 to 500 °C. The structure of the films has been studied with x‐ray‐diffraction measurements and it was found that at deposition temperature of 350 °C a face‐cubic‐centered phase is formed with a unit‐cell dimension of 0.4111 nm. At higher temperatures, up to 450 °C, the deposited films crystallize in a body‐cubic‐centered phase of tungsten with a unit cell of 0.317 nm. The complex dielectric constant (&egr;=&egr;1+i&egr;2) of the films has been measured with spectroscopic ellipsometry within the energy range 1.5–6.5 eV. The energy variation of &egr;1changes with deposition temperature; instead, that of &egr;2does not change significantly with it. The energy variation of &egr;1for the films deposited at temperatures below 400 °C corresponds to that of insulators while that of films deposited at higher temperatures, up to 450 °C, reveals their metallic character. ©1995 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.359133

出版商:AIP    

年代:1995

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.359616

出版商:AIP    

年代:1995

数据来源: AIP