摘要:

First observation of light emission due to negative differential resistance in a new optoelectronic device called an optoelectronic triangular barrier switch, which displays bistable electrical characteristics, is reported. The light emission is shown to be initiated by controlled reverse breakdown and then sustained by avalanching for the duration of the negative differential resistance part of the device electrical characteristics. The spectral content was measured and has peak emission at 0.85 &mgr;m, which corresponds to the band‐gap energy of the GaAs. It is shown that the light emission is due to the radiative recombination of electron‐hole pairs created by avalanching electrons and not due to the recombination of high‐energy electrons and holes.

ISSN:0021-8979    

DOI:10.1063/1.341040

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

The quality of a rf glow discharge depositeda‐Si:H thin film is affected by the substrate material. As a result of ion bombardment, some of the reactive species from the glass substrate are introduced into the deposition chamber by desorption. These species are then adsorbed back into the surface with the decomposed gas and form impurities in the film. The presence of Na‐Si and K‐Si impurities in thea‐Si:H film lowers the electrical conductivity and decreases the film stability.

ISSN:0021-8979    

DOI:10.1063/1.341015

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

A microindentation test of CdS single crystals is performed on the {001}, {101¯0}, and {12¯10} surfaces using the sublimation method. The plastically deformed region around the indentation mark is measured by using the chemical etching technique and the optical microscope. The typical dimension of etch‐pit arrayr&mgr;m caused by indentation is assumed as a radius of the plastically deformed region. The main results obtained are as follows: (1) The swellhfrom the crystal surface is 2–3 &mgr;m on the {101¯0} surfaces when the load of identerWis 2.94 N. (2) The microhardnessHvon the (0001) surfaces revealed the asteroid pattern and the rosette pattern are distributed 100 to 140 and 95 to 130, respectively. (3) The functional relation between the load of indenterWN and ther&mgr;m isr=53.3 (W−0.127)1/2for the asteroid pattern andr=99.9 (W−0.145)1/2for the rosette pattern of the etch pits on the (0001) surfaces.

ISSN:0021-8979    

DOI:10.1063/1.341016

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

We have studied sputtered amorphous Tb‐Fe films by torque magnetometry in the range 10–300 K.M‐Hloops have also been taken with a vibration sample magnetometer. All the samples studied show uniaxial anisotropy on the order of 1.5×106erg cm−3. The rotational hysteresis is present. The torque curves forT<80 K show a strong deviation from sin 2&thgr; behavior and makes the extraction ofKudifficult. However, in the range 80–300 K,Kuincreases strongly with a decrease in temperature. A strong contribution from magnetoelastic interactions is suggested. As regards magnetization, it increases asTdecreases and saturates forT<60 K. The results are discussed.

ISSN:0021-8979    

DOI:10.1063/1.341017

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

Very thin films of Ni, Ta, W, Pb, and Bi in a Ag matrix were irradiated at 77 K with 330 keV Kr ions at doses from 3 to 7×1015ions/cm2and analyzed at room temperature by backscattering of 1.9 MeV He+. The measured mixing efficiencies,Dt/&fgr;FD, for the various tracers correlate with their respective tracer impurity diffusion coefficients and impurity‐vacancy binding energies in Ag. The results concur with previous ones with a Cu matrix and further support the idea that the parameters that are important for thermal diffusion are also important for ion mixing in a thermal spike.

ISSN:0021-8979    

DOI:10.1063/1.341018

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

Amorphous phases in the completely immiscible Bi‐Fe system were formed for the first time by ion mixing and magnetron cosputtering. In the ion mixing experiments, multilayer samples of Bi and Fe were bombarded with energetic Fe ions. In the planar magnetron cosputtering, mixture films were prepared by simultaneously sputtering Bi and Fe atoms onto the substrates kept at liquid‐nitrogen temperature. Using Rutherford backscattering spectrometry and transmission electron microscopy, the compositions and phases of the thin alloy films were identified. The amorphous alloy formed by ion mixing is Bi50Fe50. The composition of the amorphous alloy films formed by magnetron cosputtering is in the range of 40–60 at. % Bi.

ISSN:0021-8979    

DOI:10.1063/1.341019

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

The diffusivity of the zinc Ga1−xAlxAs at 650 °C was studied using sealed‐ampoule diffusion. Whereas Ageno, Roedel, Mellen, and Escher [Appl. Phys. Lett.47, 1193 (1985)] found dramatic decreases in the zinc diffusivity atxAl≊0.05 andxAl≊0.20 using open‐tube diffusion, the results of the present study show that the sealed‐ampoule technique results in a more uniform dependence of the zinc diffusivity on aluminum concentration.

ISSN:0021-8979    

DOI:10.1063/1.341020

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

A semiclassical derivation is given of Handel’s expression [Phys. Rev. Lett.34, 1492 (1975); Phys. Rev. A22, 745 (1980); Phys. Rev. A26, 586 (1982)] for the Hooge [Phys. Lett. A29, 139 (1969); Physica83B, 19 (1976)] parameter &agr;H. This may explain why Handel’s expression for &agr;Halways agrees with the experimental data, despite the fact that there seem to be serious objections to Handel’s derivation of his results.

ISSN:0021-8979    

DOI:10.1063/1.341175

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

Semi‐insulating polycrystalline silicon (SIPOS) is a nonlinear, resistive film which is widely used as a passivant in high‐voltage planar electronic devices. We present current‐voltage and capacitance‐voltage data, taken from SIPOS capacitor structures, which are quite different from similar results in the literature. We propose that our data may be explained by the existence of a change in the current transport mechanism in the film at an anomalously low electric field value. We present an atomic resolution micrograph of the SIPOS/silicon interface which points to a possible morphological reason for the uniqueness of the current transport properties.

ISSN:0021-8979    

DOI:10.1063/1.341021

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

A concept for a bulk semiconductor switch is presented, where the conductivity is increased and reduced, respectively, through illumination with light of different wavelengths. The increase in conductivity is accomplished by electron ionization from deep centers and generation of bound holes. The reduction of conductivity is obtained by hole ionization from the excited centers and subsequent recombination of free electrons and holes. The transient behavior of electron and hole density in a high power semiconductor (GaAs:Cu) switch is computed by means of a rate equation model. Changes in conductivity by five orders of magnitude can be obtained.

ISSN:0021-8979    

DOI:10.1063/1.341022

出版商:AIP    

年代:1988

数据来源: AIP