摘要:

A new all refractory Josephson junction, in which Yb oxide is used as a tunneling barrier, has been fabricated by the self‐aligned contact process. The heat formation energy of Yb oxide is higher than that of Al oxide. It is expected that a junction with Yb oxide would be more stable than one with Al oxide. The obtained current‐voltage characteristic isVm=15 mV at the critical current densityjJ=1500 A/cm2. Its dielectric constant and barrier height are compared with Al oxide.

ISSN:0021-8979    

DOI:10.1063/1.337539

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

A new switching mechanism in a two‐terminal semiconductor heterolayer structure is proposed which capitalizes on nonlinear electron temperature effects in adjacent heterolayers. The estimated switching speed of an optimized heterostructure hot electron diode should be extremely fast, perhaps as fast as 200 fs. Data are presented on prototype devices which show the expected negative differential resistance and indicate that the basic physical model is correct.

ISSN:0021-8979    

DOI:10.1063/1.337540

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Adhesion of HgCdTe samples to fused silica ampoule walls, or ‘‘wetting,’’ during the homogenization process was eliminated by adopting a slower heating rate. The idea is to decrease Cd activity in the sample so as to reduce the rate of reaction between Cd and the silica wall.

ISSN:0021-8979    

DOI:10.1063/1.337541

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Highly aligned SmCo5deposits were produced using plasma spraying.c‐axis alignment, normal to the plane of the deposit, was achieved by depositing the Sm‐Co alloys on steel substrates maintained at high temperatures. The substrates were heated by the plasma flame to obtain the high temperatures. The attainment of a range of substrate temperatures was made possible through control over the geometry of the substrate.

ISSN:0021-8979    

DOI:10.1063/1.337542

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

An analytical method for quantitative interpretation of GaAs photoluminescence spectra was developed. Because of various transition mechanisms the photoluminescence spectrum of a sample may vary significantly under different measurement conditions. Based on a proposed scheme of transition priorities, spectra taken at various excitation powers were analyzed. Comparing results of undoped GaAs epitaxial layers grown by organometallic chemical vapor deposition under similar conditions but different V/III ratios, an optimum ratio corresponding to a minimum number of shallow impurities was clearly identified. Carbon and zinc were found to be the major shallow acceptors in most samples. At very low V/III ratios, carbon was the most dominant acceptor. The carbon concentration diminishes with an increasing ratio and the amount of zinc becomes more significant.

ISSN:0021-8979    

DOI:10.1063/1.337543

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

We report here fabrication of a super‐Schottky diode on GaAs using a novel structure. This device takes advantage of the reverse‐beveled walls of anisotropically etched GaAs. The reverse‐beveled edge acts as a shadow mask to a direct‐line evaporation of the superconducting electrodes. The controllable etch rate of the GaAs etching solution (H2O, H2O2, and H2SO48:1:1) allows for the definition of a small critical geometry (submicron) in the vertical direction without the need of electron beam lithography, or any other fine lithography system. The small critical geometry between superconducting electrodes is necessary for reduction of the parasitic‐substrate resistance.

ISSN:0021-8979    

DOI:10.1063/1.337544

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

The current waveforms of the self‐resetting oscillation in a dc superconducting quantum interference device (SQUID) are observed by means of a Josephson sampling system. The frequency of the oscillation is around 60 GHz. The time period of the self‐resetting oscillation is experimentally measured as a function of the bias current to the SQUID. Theoretical and numerical analyses are presented for the self‐resetting oscillation in the dc SQUID.

ISSN:0021-8979    

DOI:10.1063/1.337545

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

The equilibrium density of two‐dimensional electron gas in a modulation‐doped AlGaAs/GaAs heterojunction structure has been studied by considering the deep electron traps (i.e.,DXcenter) in doped AlGaAs layer, the spatial distribution of electrons in three conduction‐band minima (&Ggr;,L, andX), and the heavy doping effect. It is shown that the amount of conduction band‐bending increases and the equilibrium density of two‐dimensional electron gas decreases significantly as a result of incorporating these effects.

ISSN:0021-8979    

DOI:10.1063/1.337546

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Low‐pressure operation of an electron‐beam excited ArF laser was experimentally compared to KrF lasers, both of which were pumped at high excitation rate by a 65 ns electron beam. We obtained the ArF laser energy of 95 J with an intrinsic efficiency of 3.4% from a 650 Torr Ar/F2mixture pumped at an excitation rate of 2.3 MW/cm3. In the low‐pressure region (near one atmosphere) the Ar/F2mixture gave higher efficiency than that of Ne‐buffered mixtures, and moreover gave higher efficiency than those of the KrF lasers operating with various mixtures under the same excitation rate. As a result, the ArF laser operating in this regime is found to be a better candidate than the KrF laser as an inertial confinement fusion driver.

ISSN:0021-8979    

DOI:10.1063/1.337547

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

In a semiconductor the density of carriers in each subband fluctuates owing to intraband transitions. We consider the spectral density for number fluctuations and for conductance fluctuations arising from such intraband transitions. It is shown that the spectral density for number fluctuations equals zero. If the mobility is the same in all subbands, the spectral density for conductance fluctuations equals zero. Otherwise the conductance fluctuations show a non‐1/ fspectrum.

ISSN:0021-8979    

DOI:10.1063/1.337548

出版商:AIP    

年代:1986

数据来源: AIP