摘要:

The interface atomic structure of very thin IrSi(IrGe) films grown on the Ir(001) plane has been studied with the field ion microscope. Two distinctive types of structures have been observed. One shows theC(2×2) structure of the substrate. As the size of the layer is reduced by field evaporation, the surface relaxes into a rhombic structure resembling the (011) Ir layer of the IrSi(IrGe) crystal. The other shows a rectangular unit cell of a larger size, which is not yet successfully correlated to the structure of the IrSi(IrGe) crystal.

ISSN:0003-6951    

DOI:10.1063/1.96847

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Electron traps in dislocation‐free In‐alloyed liquid encapsulated Czochralski (LEC) GaAs have been studied by deep level transient capacitance spectroscopy. Five traps are observed with activation energies ranging from 0.26 to 0.79 eV below the conduction band. The energies are closely equal to the ones observed in undoped LEC GaAs. However, a notable difference between the In‐alloyed crystal and the undoped crystal exists in effects of annealing on the deep levels. For the In‐alloyed crystal, all levels except EL2(0.79 eV) are unstable under the annealing at 850 °C, while for the undoped crystal, levels EL5(0.41 eV) and EL2 remain stable.

ISSN:0003-6951    

DOI:10.1063/1.96848

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Resonant tunneling transport was studied in GaAs‐AlGaAs single well, double barrier structures. Negative differential resistance at 77 and 300 K was observed in devices grown by metalorganic chemical vapor deposition. The observed peak to valley ratios were 6 to 1 and 1.48 to 1, respectively. The presence of GaAs spacer layers was found to have a distinct effect on the 300 K current versus voltage characteristics. Microwave oscillation at frequencies up to 3.0 GHz was observed at 300 K. A short discussion of the oscillation frequency limits of our structure is presented.

ISSN:0003-6951    

DOI:10.1063/1.96849

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Epitaxial films of CdTe and HgTe have been grown by metalorganic chemical vapor deposition using a new tellurium source, ditertiarybutyltelluride. This compound is demonstrated to be less stable than presently available organotellurium compounds which permits film growth at lower substrate temperatures. Specular CdTe and HgTe films have been grown at temperatures as low as 220 and 230 °C, respectively. Hall measurements performed on the HgTe films indicate good transport properties. The reduced stability of ditertiarybutyltelluride compared to other alkyl organotellurium compounds is consistent with relative stability results for branched hydrocarbon molecules.

ISSN:0003-6951    

DOI:10.1063/1.96850

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

The effects of a graded composition layer at the amorphous silicon/nitride interface are studied using transient photoconductivity. The graded layer causes a large increase in the density of slow states (electrons trapped within the nitride), but does not influence the fast interface states. The kinetics of trapping and release are measured and a model of field assisted hopping and thermal excitation is proposed. The different origins of slow and fast states are also discussed.

ISSN:0003-6951    

DOI:10.1063/1.96851

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Light emission normal to the surface of a GaAs/AlGaAs wafer has been obtained by fabricating edge‐emitting double‐heterostructure diode lasers with a monolithic 45° deflector adjacent to one of the laser facets. The deflector and adjacent facet were formed by ion beam assisted etching, while the other facet was cleaved. Diode laser/deflector devices with two etched laser facets could be used to fabricate monolithic two‐dimensional laser arrays.

ISSN:0003-6951    

DOI:10.1063/1.96802

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

We report electrical transport data for holes in single strained quantum well structures of the type GaAs/InxGa1−xAs/GaAs withx≊0.2. With modulation doping, 4 K mobilities of ∼3×104cm2/V s have been achieved. This value is near that attained for electrons in comparable structures, illustrating the enhanced transport possible due to the strain‐induced light‐hole planar mass.

ISSN:0003-6951    

DOI:10.1063/1.96803

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

A self‐limiting mechanism has been observed in the atomic layer epitaxy (ALE) of GaAs deposited by alternate exposure to AsH3and trimethylgallium (TMG). The thickness of the deposited film was found to be independent of the mole fractions of both TMG and AsH3in the gas phase. These results will allow the use of ALE to deposit III‐V compounds with growth rates which are insensitive to the input partial pressures of the reactive gases.

ISSN:0003-6951    

DOI:10.1063/1.96804

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Double barrier heterostructures consisting of HgTe‐CdTe‐HgTe‐CdTe‐HgTe layers are proposed as providing improved negative differential resistance current‐voltage characteristics as compared with similar devices based on the GaAs‐GaAlAs system. The small HgTe‐CdTe valence‐band offset and the inverted light holelike conduction band of HgTe produce intrinsic interface states with long decay lengths in the CdTe barrier layers. This enhances the transmission coefficient and thus the tunneling current. Also, the small offset causes the CdTe barriers to present more blockage to unwanted thermal electron currents than do typical GaAlAs barriers. The high mobility of HgTe reduces the series resistance of the contacting layers, thus reducing the bias voltage required to achieve resonance and increasing the speed of the device. The effectiveness of the structure will depend on the value of the valence‐band offset and material quality.

ISSN:0003-6951    

DOI:10.1063/1.96805

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Low‐temperature photoluminescence studies of undoped, N+(nitrogen)‐implanted and C+(carbon)‐implanted AlAs grown by molecular beam epitaxy are reported. It was experimentally demonstrated that a dominant emission temporarily denoted byA, observed at 13 meV below the indirect excitonic band gap,Eg,ind(X), is closely related with N isoelectronic impurity atoms. It was also found that theAemission accompanies many one‐phonon and two‐phonon replicas, among which the longitudinal optical phonon replica is predominant. Carbon atoms were determined not to be principal residual impurities in undoped AlAs. The two conspicuous C‐related emissions were revealed by the intentional incorporation of C atoms, which are situated at 60 and 64 meV belowEg,ind(X).

ISSN:0003-6951    

DOI:10.1063/1.96806

出版商:AIP    

年代:1986

数据来源: AIP