摘要:

Results of an experimental investigation of the effects of uniaxial stress on the magnetically induced velocity changes for 5‐MHz surface (Rayleigh) waves in specimens of ASTM A‐36, SAE 4340, and HY‐80 steel are described. Like the magnetically induced velocity changes for ultrasonic shear and longitudinal waves, the magnetically induced velocity changes for surface waves exhibited characteristic stress effects which were dependent on the magnitude and the sign (tensile or compressive) of the stress as well as on the relative orientation of the stress, the magnetic field, and the wave propagation directions. The observed characteristic stress effects indicated potential applicability of the magnetically induced velocity changes for surface waves to nondestructive measurements of residual surface stresses in ferromagnetic structural steels.

ISSN:0021-8979    

DOI:10.1063/1.335614

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

The directional amplified spontaneous emission (ASE) along the laser tube of an iodine photodissociation laser (IPL) amplifier is measured and the experimental results are compared with the one‐dimensional ASE theory. Also, we have measured the loss of the stored energy in the IPL amplifier due to the omnidirectional ASE. The loss is found to be 13.5% for the present amplifier when the laser mediumi‐C3F7I is 72 Torr and no argon buffer gas is added. But by adding the argon buffer gas to 210 Torr, it is reduced to 4.2%.

ISSN:0021-8979    

DOI:10.1063/1.335615

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

The information obtained by deep level transient spectroscopy (DLTS), used to investigate insulator‐semiconductor interfaces, is studied by using basic statistical theory. It is shown that in a modified form of DLTS the Gibbs free energy of the interface traps is obtained, while the standard DLTS gives the enthalpy values. An important consequence is that the ‘‘electronic degeneracy factor’’ cannot be obtained from this type of measurement.

ISSN:0021-8979    

DOI:10.1063/1.335564

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

Transient current measurements have been performed on Pd‐gate metal‐oxide‐semiconductor capacitors at zero bias and room temperature, during hydrogen absorption and desorption. It is shown that a simple relationship among transient current, flat‐band voltage, and time‐dependent capacitance can fit the experimental data. Different possible origins of the transient current phenomenon are considered and discussed and the role played by the Na+in delaying the transient current response is also illustrated.

ISSN:0021-8979    

DOI:10.1063/1.335565

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

We report on the optical transmission properties of narrow‐band‐gap (Eg<0.1 eV) InAs/GaSb superlattices grown by molecular‐beam epitaxy. Energy band gaps of 0.15 and 0.085 eV at 4.8 K are determined for a 102‐A˚‐period and a 124‐A˚‐period superlattice, respectively. The absorption edge is extremely soft due to the spatial mismatch of hole and electron wave functions. In addition we show the first reported x‐ray diffraction measurements on this materials system.

ISSN:0021-8979    

DOI:10.1063/1.335566

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

The effects of high‐field stressing (9–10 MV/cm) with positive gate voltage on charges and defects in the SiO2layer of metal‐oxide‐semiconductor structures are reported. In Al‐gate devices negative charge builds up near the Si‐SiO2interface whereas positive charge is generated near the Al‐SiO2interface. Subsequent avalanche injection of electrons into the oxide does not annihilate the positive charge but the negative charge disappears. Similar studies were performed on polycrystalline silicon gate devices for which internal photoemission (photoI‐V) measurements are reported for the first time. In this case a negative charge distribution is observed near both SiO2interfaces after a positive stress and additional electron traps are created near the noninjecting polycrystalline silicon/SiO2interface. Similarly, a negative stress for a polycrystalline silicon gate device creates electron traps near the substrate Si‐SiO2interface, as reported previously for Al‐gate devices.

ISSN:0021-8979    

DOI:10.1063/1.335567

出版商:AIP    

年代:1985

数据来源: AIP