摘要:

We have prepared several thicknesses of ∼1 cm by ∼1 cm epitaxial single crystals of AlN with a ’’high temperature (∼1800 °C) close‐spaced vapor transport’’ technique. These crystals have been grown both on (011¯2) and (0001) sapphire wafers. The optical absorption edge is measured at 300 K and for the first time at low temperature (5 K). This data is parametrized to include both reflection losses due to scattering off surface imperfections and contributions from impurity absorption bands. This parametrization technique is used to determine the band gap and the nature, direct or indirect, of the absorption edge. A value of 6.28 eV was found to be the best value ofEg(5 K) and the gap was found to be direct.

ISSN:0003-6951    

DOI:10.1063/1.90354

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

The duration time of pulsed oscillation of an H2O laser was considerably elongated at 16.93, 27.97, and 36.60 &mgr;m, by adding large amount of helium gas to the discharge. The admixture of He was also effective in enhancing the output power.

ISSN:0003-6951    

DOI:10.1063/1.90355

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

The development of a high peak and average power stimulated Raman scattering (SRS) source with a dye amplifier is described. Emission from 505 to 771 nm is obtained using 532‐nm radiation from a frequency‐doubled Nd : YAG laser as the optical pump. Dimethyl sulfoxide (DMSO) is found to be a very efficient SRS medium, and produces 40% energy conversion from 532 to 630 nm at 10 pulses/sec. Use of a dye amplifier increases energy conversion efficiency to 60%. Mixtures of DMSO andd‐DMSO are found to emit the I and II Stokes lines of each material, plus a ’’mixed’’ mode line at 727 nm. SRS is also shown to be a limiting phenomenon in the power scaling of laser‐pumped dye lasers.

ISSN:0003-6951    

DOI:10.1063/1.90356

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

This letter reports the inversion and intense superfluorescent emission of the Na resonance line by selective photodissociation of NaI. The fifth harmonic of aQ‐switched Nd : YAG laser at 2128 A˚ was used to photodissociate NaI to the unbound state Na(3p 2P)+I(5p5 2P3/2). Superfluorescence at the 5896‐A˚ resonance line was observed.

ISSN:0003-6951    

DOI:10.1063/1.90357

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Low‐current cw stripe double‐heterostructure (DH) lasers have been realized using a shallow proton‐bombardment technique; unlike usual proton DH lasers they involve a resistivep(GaAl)As confinement layer and a rather highly doped GaAs active region both to reduce spreading current and stripe injected carrier outdiffusion. Threshold currents are on the order of 50 mA for a 12‐&mgr;m‐wide by 200‐&mgr;m‐long cavity.

ISSN:0003-6951    

DOI:10.1063/1.90358

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

The deep‐level emission at 1.0 eV is analyzed to be associated with the slow degradation of GaAlAs DH laser diodes. The intensity of this deep‐level emission increases at the same rate as the increase in the threshold current during the slow degradation. The carrier lifetime does not change correspondingly to the increase in the threshold current. This deep level is considered to act as the photon‐absorption center to cause the increase in the threshold current.

ISSN:0003-6951    

DOI:10.1063/1.90359

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Conduction of polycrystalline boron nitride films in a form of a Ag‐BN‐Si‐Al sandwich has been investigated. After electroforming, the samples exhibit threshold switching in atmospheres which contain moisture. The switching is well explained by Dearnaley’s filamentary model.

ISSN:0003-6951    

DOI:10.1063/1.90360

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Impact‐ionization current during saturation mode operation is widely known in MOS devices. Although not noted in previous work, minority carriers also may be observed in the substrate, together with hole current. These minority carriers can degrade the MOS depletion layer lifetime, thus limiting the performance of MOS dynamic devices. A series of experiments utilizing theC‐tmethod, the MOS capacitor surface potential measurement, and the charge‐coupled device (CCD) is described, which provides evidence for electrically generated electrons in the substrate ofn‐channel MOS structures.

ISSN:0003-6951    

DOI:10.1063/1.90361

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

A technique forp‐njunction formation in silicon, based on deposition of boron on silicon atroomtemperaturefollowed by laser irradiation is described. Transmission electron microscopy and electrical measurements indicate that as a result of the laser irradiation the boron is dissolved in the silicon and becomes electrically active. Diode characteristics ofp‐njunctions produced by this technique are quite good. The dopant profile distribution has been obtained using secondary ion mass spectrometry and is in qualitative agreement with simplified theoretical calculations.

ISSN:0003-6951    

DOI:10.1063/1.90368

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Postgrowth annealing of plasma grown GaAs oxides in N2and H2result in very different electrical behaviors. By examining cross‐sectioned specimens of these oxides with transmission electron microscopy, and correlating the observed structure with electrical measurements, it is demonstrated that metallic As at the oxide‐semiconductor interface plays a significant role in determining the MOS characteristics.

ISSN:0003-6951    

DOI:10.1063/1.90329

出版商:AIP    

年代:1978

数据来源: AIP