摘要:

This paper deals with a model of silicon oxidation including stress relaxation by viscous flow during growth. Based on a Deal–Grove process and a Maxwellian stress relaxation approach, an integrodifferential equation giving the inverse growth ratedt/deoxvseoxis established. Valid in any case of thickness growth rate dependence, it allows us to fit dry silicon oxidation data on a wide range of oxidation temperature (780–980 °C).

ISSN:0021-8979    

DOI:10.1063/1.331986

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

An investigation was conducted to determine the effects of piezoelectrically coupled stresses on the capacitance, open‐circuit voltage, short‐circuit current andI‐Vcharacteristics of CdS‐Cu2S solar cells. The theoretical analysis suggests that only nonuniform stresses will result in changes in the open‐circuit voltage and capacitance. This was consistent with measurements made under uniform and nonuniform stress. Furthermore the direction of the change was consistent with that expected for junctions formed on the polar S face or the Cd face. The short‐circuit current and theI–Vcharacteristics are, however, sensitive to both uniform and nonuniform stress but insensitive to the polar face on which the cell is formed. This suggests a nonpiezoelectric stress effect for these characteristics. The measurements were made at relatively low levels of stress (∼2 to 4×107N/m2) and stress gradients (∼2×1010N/m3). Under these conditions the measured changes are 1% or less. Thus the built‐in stresses resulting from cell manufacture are not expected to have a significant effect on cell properties unless they are at least an order of magnitude larger.

ISSN:0021-8979    

DOI:10.1063/1.331987

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

The production of work by devices receiving radiant energy and interacting with a local environment is discussed. Provision is made for the device to radiate at a temperature different from the local environmental temperature. The resulting conversion efficiency is discussed in terms of the radiant source, emitting and environmental temperatures. The environment is seen to play a pivotal role in the production of work. Extrema in the efficiency function are examined and no true maxima are found to exist. However, there are optimum choices for the emitter temperature if we hold the environmental temperature constant, and conversely. A case is demonstrated for which the device may absorb an amount of heat from the environment and perform an equal amount of work.

ISSN:0021-8979    

DOI:10.1063/1.331988

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

The ablation of electrode surfaces has been observed for several materials illuminated by radiation from an imploding wire array. The experiments were done on the PITHON 5‐TW generator. A plasma boundary atne=5×1018/cm3expands at velocities up to 10 cm/&mgr;s from the surface. Calculations suggest early vacuum‐ultraviolet radiation ablates the electrode surface. Hydrogen is the dominant element forming a coating on the electrode surface.

ISSN:0021-8979    

DOI:10.1063/1.331989

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

A model of ap‐i‐nthin‐film solar cell is presented that can be easily used to analyze solar cell properties. The continuity equations are solved using the regional approximation, producing elementary solutions that give insight into the physics of the transport in the cell. The steady‐state solutions are compared with measurements on typical hydrogenated amorphous silicon,a‐Si:H, solar cells. The ac solutions are used to explain a new source of photocapacitance due to mobile carriers.

ISSN:0021-8979    

DOI:10.1063/1.331955

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

In1−xAlxAs epitaxial layers were grown on (100) InP substrates by the organometallic vapor phase epitaxy method. Undoped layers with mirror smooth surfaces were obtained for substrate temperatures of 600–650 °C. By adjusting the relative ratio of In and Al, lattice matched In0.52Al0.48As epilayers were reproducibly grown on InP substrates. X‐ray measurements, scanning Auger analyses, and electron mobilities are presented. These results show that the quality of the epilayers obtained here was comparable to the best reported layers grown by other methods.

ISSN:0021-8979    

DOI:10.1063/1.331956

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Data are presented showing that wavelength modification, of at least 210 A˚ (from 8180 to 7970 A˚), of broad area room temperature pulsed quantum well heterostructure (QWH) laser diodes is possible by thermal annealing. Thermal annealing at 900 °C for 8 h results in only a minor change in the threshold current density, 385–425 A/cm2, thus making possible similar wavelength modification (8180–8080 A˚) ofcontinuous(cw) 300 K stripe‐geometry QWH laser diodes.

ISSN:0021-8979    

DOI:10.1063/1.331957

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

The role of the Pierce instability in the formation of double layers is considered and compared with that of the Buneman instability. Pierce instabilities have been identified in a double‐layer experiment, where they lead to ion trapping. Here the effects of external circuit elements are considered. In the case of immobile ions the onset criteria are unaffected, but in the unstable range the growth rate is reduced by the external impedance. Required experimental values of the circuit elements are estimated. The possible relevance to computer simulations is noted.

ISSN:0021-8979    

DOI:10.1063/1.331958

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

The manner in which projectile velocity in a rail gun is limited by the presence of atmosphere in the gun tube is studied. In particular, we solve the equation of motion for the acceleration of the armature and projectile, accounting for both the decelerating force exerted by the atmosphere and the time decay of the current profile. From the solution, a characteristic time is derived which indicates quantitatively when the effect of the atmosphere can be expected to be significant. Results of the calculation are then compared qualitatively with results from two recent experiments: one in which atmospheric effects are nearly negligible and one in which they are not.

ISSN:0021-8979    

DOI:10.1063/1.331959

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

A model is proposed to explain observations of inhomogeneous yielding in shocked solids. Instead of seeking hydrodynamic or elastic‐plastic instabilities in an initially homogeneous specimen, it is proposed that the material under shock conditions (at pressures well above the yield strength) may be characterized as a viscous medium with initially inhomogeneous viscosity. Such a viscosity might be caused by an inhomogeneous distribution of dislocations. Assuming that the viscosity also decreases with temperature in a simple way, suitably truncated hydrodynamic equations can be solved analytically and predict a tendency toward runaway of temperature and deformation in localized regions.

ISSN:0021-8979    

DOI:10.1063/1.331960

出版商:AIP    

年代:1983

数据来源: AIP