摘要:

Weak laser oscillation has been demonstrated on the 489‐ and 777‐nm electric‐dipole‐forbidden1S0–3P1and1S0–1D2transitions of the selenium atom. Carbonyl selenide has been photolyzed at 172 nm by Xe*2radiation to produce the Se(1S0) excited state.

ISSN:0003-6951    

DOI:10.1063/1.90294

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

A new type of high‐low‐junction emitter silicon solar cell employing an oxide‐charge‐induced electron accumulation layer demonstrates complete suppression of the dark emitter recombination currentJEto values so low that the base recombination current dominates in determining the open‐circuit voltageVOC. This suppression ofJEresults in measured values ofVOCconsiderably larger than those previously reported forn‐on‐psilicon solar cells. This ability to suppressJEleads to projections of efficiency of about 18% AM0 and about 20% AM1 for this oxide‐charge‐induced high‐low‐junction emitter (OCI‐HLE) solar cell.

ISSN:0003-6951    

DOI:10.1063/1.90295

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Operation of a LOC‐DBR laser which exhibits high differential quantum efficiency is reported. It is shown that this result is obtained by further reduction of losses in the unpumped regions of the laser, especially, excessive absorption losses due to nonuniform Al carryover in the thin ’’GaAs’’ layer.

ISSN:0003-6951    

DOI:10.1063/1.90296

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Distributed‐feedback Ga1−xAlxAs lasers with a channeled‐substrate‐planar structure are fabricated. They operate in single transverse and longitudinal modes. No spectral broadening or excess noise is observed under high‐frequency modulation as a result of mode stabilization.

ISSN:0003-6951    

DOI:10.1063/1.90297

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

In this work a dilute nitrogen plasma pumped by charge transfer from He+2has been operated as a pulsed optical amplifier. In the experimental system used two synchronously excited plasmas were produced by preionized discharges in an atmospheric electrical avalanche device switched by hydrogen thyratrons so that repetitive operation to 30 Hz would be possible. The plasmas were electrically connected in a transverse series circuit to provide a phase delay in their excitation comparable to the optical transit time between them. Laser output at 427.8 nm from the first discharge coupled to the fields in a self‐excited oscillator geometry was threaded through the second along its 85‐cm longer dimension. Calibrated attenuation of the beam from the oscillator subsequently input to the amplifier provided data on the overall amplification ratio to which the two adjustable parameters of a simple model were fit. From these parameters overall small‐signal gains as large as 2×106were found together with saturation intensities of the order of 50 kW/cm2. Under the same conditions a gain of about 18 was found at an output intensity of 1 MW/cm2, conditions relatively near the ideal extraction of power at zero gain.

ISSN:0003-6951    

DOI:10.1063/1.90298

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

It is shown that the insulating layer in metal‐insulator‐semiconductor (MIS) solar cells by no means has to be perfect to obtain optimum photovoltaic performance. Oxide pinhole densities as large as 1000 cm−2can be tolerated without degrading the device properties. Large densities of oxide traps at energies close to the majority‐carrier band edge in the semiconductor can reduce the cell efficiency as can surface states in nonoptimal devices. Devices optimally designed with an inversion layer at the IS interface are virtually immune to these states, densities in excess of 1013cm−2causing no degradation in properties.

ISSN:0003-6951    

DOI:10.1063/1.90299

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

High‐quality GaP layers were obtained by liquid phase epitaxy at a low temperature, 650 °C, from indium solvent. We attribute the high quality of the LPE layers to the reduction in the concentrations of vacancies and unintentional impurities such as Si which would come from the growth system.

ISSN:0003-6951    

DOI:10.1063/1.90300

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Studies of intensity‐dependent transmission of pulsed radiation of nanosecond duration at 10.6 &mgr;m very near the band gap inn‐Hg0.77Cd0.23Te at low temperatures show evidence of abrupt limiting behavior which manifests itself in no additional transmission for incident intensities exceeding approximately 200 kW/cm2atT⩽20 K. Measurement of the spectral broadening in the transmitted radiation for excitation of nanosecond duration suggest that such self‐enhanced ’’opacity’’ can be switched on in less than 500 psec. The surprisingly low observed threshold intensities are considered by examining the contribution from inelastic hot‐electron collisions to the generation of excess free carriers.

ISSN:0003-6951    

DOI:10.1063/1.90301

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Ohmic contacts andp‐njunctions inp‐ andn‐type silicon are generated with the aid of a laser. Doping was achieved by covering the surface of the silicon with a layer of dopant and melting locally with pulses from either a Nd : YAG or a CO2laser. Typical residual resistances of the Ohmic contacts are of the order of 0.1–1 &OHgr; cm2and backward/forward resistance ratios of 104were measured for the diodes. A model which takes account of segregation during the cooling process is discussed and shown to agree with the resulting distribution of dopant. Highly doped material was found in a surface layer of a thickness less than 0.5 &mgr;m. This thickness was independent of laser parameters.

ISSN:0003-6951    

DOI:10.1063/1.90302

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

4He+backscattering spectrometry and x‐ray diffractometry have been used to study the formation of Ni and Pt silicides in Si(xtl)/Mfilm structures with different metal film thicknesses ranging from 800 to 5000 A˚. Results clearly show that first the phase richer in metal (Ni2Si, Pt2Si) grows and continues to grow until all available metal is reacted, then the phase richer in Si (PtSi, NiSi) starts to grow. Present results prove that in Si(xtl)/Pt or Ni interactions the growth phase is determined by the reaction kinetics and that diffusion of metal atoms through Pt2Si and Ni2Si is fundamental in keeping the reaction going.

ISSN:0003-6951    

DOI:10.1063/1.90269

出版商:AIP    

年代:1978

数据来源: AIP