摘要:

A laser melting method for preparing rhenium films on permalloy substrates is proposed. Main processes of the method include melting of pressed rhenium powders on substrates by a pulsed Nd‐YAG laser beam to form around 30‐&mgr;m‐thick rhenium films, tightly bound to the substrates. Optimum conditions for the film preparation are investigated by computer simulation and experiments. Changes in density and thermal conductivity of a powder layer at the melting temperature are introduced in the simulation. It is demonstrated that, by using this method, high melting point films can be prepared on low melting point substrates.

ISSN:0021-8979    

DOI:10.1063/1.327960

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

The effect of added acetylene on the rf discharge chemistry of C2F6was studied as a function of acetylene concentration. The principle products are HF, CF4, CHF3, C2F4, and CF2as determined by mass spectrometry. Under conditions typically used for etching SiO2, residence time and power density control the amount of conversion of feed gas to products. Large amounts of polymeric material, with composition (CF)n, are formed in the discharge zone. A chemical model for flourocarbon discharges is proposed, which assumes an equilibrium between dissociation and recombination of flourocarbon fragments and flourine atoms. Polymerization and selective etching of Si and SiO2in flourocarbon dishcarges containing oxygen or hydrogen additives is interpreted in terms of the proposed model.

ISSN:0021-8979    

DOI:10.1063/1.327961

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

An investigation of the backwall MIS Schottky barrier solar cell model was made. This model incorporates the following factors which, for the most part, determine the behavior of the device: the short circuit current density, the MIS Schottky barrier junction behavior, and resistive losses. The study concentrated on the Al‐Al2O3‐GaAs‐metal structure. Practical energy conversion efficiencies are predicted for this structure for a variety of semiconductor properties ranging from best‐ to worst‐case conditions. Reflection losses are ignored assuming that the proper antireflective coating will minimize these losses. The study of the short circuit current density indicates that the structure must be that of a thin‐film semiconductor with maximum current occurring when the GaAs thickness is in the 500‐A˚ to 1.2‐&mgr;m range, depending on minority carrier diffusion length and surface recombination velocity. The behavior of the Al‐Al2O3‐GaAs Schottky barrier junction yields an optimum open circuit voltage for an Al2O3thickness of about 15 A˚. The resistive loss study considered both the metal ohmic contact grid structure and the semiconductor resistivity. Conversion efficiencies as high as 6% are predicted for this structure with rather poor electrical properties of the GaAs films, i.e., &mgr;n=10 cm2/V sec, &mgr;p=1 cm2/V sec, and an infinite surface recombination velocity. Thus, if care is taken in the design and fabrication of a backwall MIS Schottky barrier solar cell, reasonable efficiencies can be achieved even if the semiconductor has poor electrical properties, as expected for a polycrystalline film.

ISSN:0021-8979    

DOI:10.1063/1.327962

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

A system generating electromotive force in isothermic conditions has been described. The effect appears against the background of thermionic emission obtained from a couple of electrodes working in a magnetic field.

ISSN:0021-8979    

DOI:10.1063/1.327963

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

A detailed experimental examination of the dc critical supercurrent densityjcand the microwave (nonzero voltage) supercurrentj&mgr;has been made in proximity effect thin‐film weak links at temperatures above the transition temperature of the link material. These results were correlated with measured dimensional and superconducting parameters of the thin films and the link via a Ginzberg‐Landau (GL) formalism. In the steady state,jcwas found to be adequately described by a one‐dimensional GL formalism similar to that of Likharev and Yakobson but with De Gennes boundary conditions on the order parameter applied at each interface. However,j&mgr;decreases exponentially with increasing voltage and can be interpreted in terms of an interference modulation of the induced pair density within the line at the Josephson frequency.

ISSN:0021-8979    

DOI:10.1063/1.327964

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

The forward current‐voltage (If‐Vf) characteristics of (50 wt% Ni– 50 wt% Pt) silicide Schottky diodes, formed in vacuum at 425 °C from rf sputter‐deposited Ni and Pt thin films, were found to be dependent on the metal‐deposition sequence. From the thermionic emission equation an empirical barrier height of 0.70 eV was calculated for diodes formed from 125 A˚ Pt/325  A˚ Ni/(111) Si, while diodes formed from 325 A˚ Ni/125A˚ Pt/(111) Si had an empirical barrier height of 0.65 eV. The deposition of a thin W‐Ti diffusion marker film on the Si surface before sputter deposition of Ni and Pt layers modifiedIf‐Vfcharacteristics. Silicide diodes formed from 125 A˚ Pt/325 A˚ Ni/(W‐Ti)/(111) Si had an empirical barrier height of 0.66 eV. Diodes formed from 325 A˚ Ni/125 A˚ Pt/(W‐Ti)/(111) Si had an empirical barrier height of 0.70 eV. MeV4He+backscattering spectra revealed that diodes with similarIf‐Vfcharacteristics had similar Ni and Pt concentration profiles in the silicide film.

ISSN:0021-8979    

DOI:10.1063/1.327965

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

The specific contact resistance for a pulse plated and alloyed Au‐Zn (16 at. % Zn) contact onp‐type Ga0.28In0.72P0.39As0.61was found to be 3.60.4×10−5&OHgr; cm2. Results of Rutherford backscattering measurements with 1.8‐MeV4He+showed that the alloyed Au moved only ∼1500 A˚ into the quaternary layer, while In and GaAs were displaced to the surface.

ISSN:0021-8979    

DOI:10.1063/1.327966

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

Carrier removal inn‐type GaAs induced by proton and deuterium bombardment has been investigated using capacitance‐voltage profiling techniques. It is shown that deuterium offers advantages over hydrogen implantation, that ’’cold’’ (30 K) implants are superior to room temperature implants, and that carrier removal depth appears to be dose dependent, or dose and dose rate dependent.

ISSN:0021-8979    

DOI:10.1063/1.327967

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

A dc‐operated thin‐film electroluminescent cell is fabricated by the use of a heterojunction contact ofn‐Ge to ZnSe as an efficient electron injector. The typical display performance of the cell havingn‐Ge‐ZnSe:Mn2+‐ITO structure is 100 fL in brightness and 16 mlm/W in luminous efficiency at 24.1 V×10mA.

ISSN:0021-8979    

DOI:10.1063/1.327968

出版商:AIP    

年代:1980

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.327969

出版商:AIP    

年代:1980

数据来源: AIP