摘要:

The photolysis of disilane (Si2H6) and trisilane (Si3H8) under direct excitation by light from a low pressure mercury lamp was carried out to prepare hydrogenated amorphous silicon films (a‐Si:H). The electronic and optical properties of the films were investigated as functions of preparation conditions such as partial pressure and substrate temperature. The conductivity of the films prepared from Si3H8at 300 °C was 10−10S cm−1in the dark and 10−5S cm−1under the illumination of a He‐Ne laser with a photon flux of 1015cm−2s−1. The high photoconductivity was attained when the silane gas was blown over the substrate from a slit‐type nozzle placed beside the substrate plate at a pressure of less than 20 Torr.

ISSN:0003-6951    

DOI:10.1063/1.96915

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Photoluminescence from ZnTe‐CdTe strained‐layer superlattices has been observed for the first time. Superlattices with CdTe and ZnTe layer thicknesses between 20 and 51 A˚ have been compared with CdxZn1−xTe alloys. The superlattices display intense visible photoluminescence which is observed at lower energies than for corresponding alloys. Both the intensities and energies of the luminescence indicate good superlattice structure. Second orderk⋅pcalculations have been performed and are found to be in agreement with experiment. Substrates greatly lattice mismatched to the superlattice are shown not to play a role in determining the band gap as the lattice constant jumps to that of the free‐standing superlattice.

ISSN:0003-6951    

DOI:10.1063/1.96916

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

We propose a new general principle of operation for solid‐state devices, and demonstrate a novel transistor which we call a double‐injection field‐effect transistor, based on this principle. We have fabricated amorphous silicon alloy double‐injection transistors operating on the modulation of a double‐injection current by a gate field covering the complete path of the current channel. Using these amorphous silicon alloy double‐injection transistors, we have achieved currents over 20 times those theoretically possible for conventional amorphous silicon field‐effect transistors operating under similar conditions. This new principle, applicable to both thin‐film amorphous and crystalline devices, offers the potential of high‐current, high‐speed field‐effect transistors with modulated optical emission.

ISSN:0003-6951    

DOI:10.1063/1.96917

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Simultaneous infrared (1152 nm) and visible (633 nm) reflectivity measurements with nanosecond resolution were used to study the initial formation and subsequent motion of pulsed KrF laser‐induced ‘‘explosively’’ propagating buried molten layers in ion implantation‐amorphized silicon. The buried layer velocity decreases with depth below the surface, but increases with KrF laser energy density; a maximum velocity of about 14 m/s was observed, implying an undercooling‐velocity relationship of ∼14 K/(m/s).Z‐contrast scanning transmission electron microscopy was used to form a direct chemical image of implanted Cu ions transported by the buried layer and showed that the final buried layer thickness was <15 nm.

ISSN:0003-6951    

DOI:10.1063/1.96918

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

A new etching procedure for GaAs substrates and a modified configuration of selectively dopedn‐AlxGa1−xAs/GaAs heterostructures have been developed for molecular beam epitaxy to reduce the density of oval defects and the epitaxial growth time. The new simplified substrate preparation method reduces the oval defect density to less than 100 cm−2and allows storage of prepared substrates in air under dust‐free conditions for several weeks without any degradation. Modification of the layer structure reduces the throughput time to less than 30 min per wafer including epitaxial growth, wafer exchange, heat and cool times. High mobilities of the two‐dimensional electron gas and excellent reproducibility are achieved. The new process uses the favorable growth rate of <1 &mgr;m/h for GaAs and thus allows growth of nearly 500 high‐quality heterostructure wafers for device fabrication without exposure of the growth chamber to atmosphere for effusion cell recharging.

ISSN:0003-6951    

DOI:10.1063/1.96919

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Epitaxial films of CdTe and (Cd,Mn)Te were grown on (001) GaAs substrates in a vacuum evaporator. Conventional Bragg diffraction indicated that the films had a single orientation, either (a) CdTe(001) ∥ GaAs(001), or (b) CdTe(111) ∥ GaAs(001). Grazing‐incidence x‐ray diffraction showed that most of the films had both orientations with (a) CdTe[110] ∥ GaAs[110] and (b) CdTe[112¯] ∥ GaAs[110]. Only one of the two possible domains was found in case (b). A mosaic of well‐crystallized islands appears to accommodate the large film strain of −12.8% due to the lattice mismatch between CdTe and GaAs.

ISSN:0003-6951    

DOI:10.1063/1.96920

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

X‐ray photoelectron spectroscopy (XPS) has been applied to characterize the damage introduced into SiO2by ion implantation. By measuring the peak width of Si2pfrom SiO2which corresponds to perturbation of the SiO2network, good depth profiles of the damage have been obtained for implanted samples and subsequently annealed samples. The results show that the damage distributed more widely than that calculated from energy deposition and that the perturbation of the network is caused not only by radiation damage but also by the existence of impurities in the network. It has been found that the XPS method is effective to understand the atomic structure, and thus, electrical properties of SiO2.

ISSN:0003-6951    

DOI:10.1063/1.96921

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Boron‐doped silicon samples with a submonolayer coverage of copper were sputter profiled under O+2bombardment at energies between 4 and 12 keV and impact angles of 2° and 32°. The profiles of Cu+secondary ions showed a peak due to the buildup of oxygen in the sample. Under conditions of incomplete oxidation (at 32°) the Cu+intensity beyond the peak decreased exponentially with a decay length of about 39 nm (8 keV O+2). By contrast, beam induced SiO2formation (at 2°) resulted in a rather abrupt decrease of the Cu+intensity (factor of 10 within a sputtered depth of 1.3–3 nm depending on the beam energy). The effect is attributed to very rapid diffusion of copper away from the surface oxide (beam induced segregation).

ISSN:0003-6951    

DOI:10.1063/1.96922

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

The derivation of the critical current or critical current density distribution from an analysis of the voltage‐current characteristic of a composite superconductor is discussed. Critical current distributions have been obtained for three Nb‐Ti composites in quite different metallurgical states. The distribution is shown to be markedly broadened when sausaged filaments produce an extrinsic limit on the composite critical current.

ISSN:0003-6951    

DOI:10.1063/1.96923

出版商:AIP    

年代:1986

数据来源: AIP

ISSN:0003-6951    

DOI:10.1063/1.97032

出版商:AIP    

年代:1986

数据来源: AIP