摘要:

The one‐flux analysis of double‐heterostructure bipolar transistors with composite collectors in the preceding article W. R. McKinnon, J. Appl. Phys. 79, 2762 (1996) is compared to drift‐diffusion calculations and to measurements on InP/InGaAs/InP/composite collectors‐double heterostructure bipolar transistors. For quantitative agreement we include the effects of ionized impurities in the space‐charge regions, and an approximate treatment of Fermi–Dirac statistics. ©1996 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.361108

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

We report on the fabrication and physics of mesa‐etched light‐emitting diodes (LEDs) made from GaNp‐njunctions grown by molecular beam epitaxy. Rapid thermal annealing was found to improve the electrical properties of these LEDs. Annealed LEDs turn on at 4 V, exhibit an on‐series resistance of approximately 14 &OHgr;, and have only 36 &mgr;A of leakage current for reverse bias levels as high as 10 V. Electroluminescence (EL) spectra obtained from devices driven to 15 mA are dominated by a peak at 400 nm, which is attributed to recombination between shallow donors and Mg luminescent centers on thepside of the junction. The full width at half maximum of this peak is only 30 nm, which, to the best of our knowledge, is the narrowest EL peak measured from a GaNp‐njunction LED. In other devices, recombination was found to proceed through defect states in the middle of the band gap. The broad emission from these LEDs can be shifted from the orange to the violet spectral region by adjusting the drive current. In addition, these LEDs withstand dc current densities in excess of 700 A/cm2at room temperature. ©1996 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.361109

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

Excitonic photoluminescence (PL) peaks from hexagonal GaN epilayers were investigated making a connection with the analysis of the photoreflectance spectra. Free exciton emissions associated with transitions from the conduction (&Ggr;7c) band to the A (&Ggr;9v) and B (&Ggr;7uv) valence bands are dominant above 100 K. Values of the full widths at half maximum of them were smaller than the thermal energykBT up to room temperature, which suggests the dominance of excitons in the PL spectra. ©1996 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.361110

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

Ar/H2sputtering of a SiO2target can produce thick silicon oxide films with significantly reduced internal stresses compared with those of conventional films prepared by an Ar/O2sputtering method. As an origin of the stress reduction, we proposed previously the structural relaxation model of the Si–O–Si network via partial Si–H termination. This model is experimentally supported here by the Raman spectroscopy measurements which show a large decrease of planar three‐ and four‐fold ring‐type defects in the hydrogenated Si–O–Si network structure. ©1996 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.361111

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

A general formalism is presented to study hot carrier relaxation in the valence band of strained and unstrained semiconductors. The approach is based on a six‐bandk⋅pdescription of the valence band and an anisotropic Monte Carlo method. We show the results of our studies for the Si–Ge system. Carriers are initially injected in the split‐off band and the carrier distribution is followed in time. Results are presented for energy‐dependent energy relaxation time. The relaxation times for Si are about 10−13s while those for Ge are an order of magnitude higher. To study the effect of biaxial strain produced through epitaxy on energy relaxation times we present results for Si0.8Ge0.2on a {100} silicon substrate. This work is of relevance to the interpretation of pump‐probe experiments, which are primarily dependent on the relaxation of the average of the carrier energy. ©1996 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.361112

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

A CuInSe2‐based thin film solar cell fabricated by the selenization method was investigated by micro‐Raman‐spectroscopy. By measuring the depth‐profile of spatially‐resolved Raman spectra taken from the cross section of the cell, the formation of MoSe2at the Mo/CuInSe2interface was confirmed. ©1996 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.361095

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

An analytical solution of the breakdown voltage for 6H‐silicon carbidep+njunction has been derived by employing an effective ionization coefficient. The breakdown voltage extracted from our analytical model agrees fairly well with the experimental data in the range of 1016–1018cm−3doping levels. ©1996 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.361113

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

Photovoltage generation was observed for C60/Si heterojunction fabricated by the deposition of C60thin film on Si substrate. Four types of Si substrates (two forp‐type and two forn‐type) were used. All junctions showed rectifying behaviors and photovoltage generation under illumination of Ar‐ion laser. The highest value of the photovoltage was 0.40 V. From the saturated photovoltage values for four junctions, the Fermi level of C60thin film was estimated to be located about 4.7 eV below the vacuum level. ©1996 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.361114

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

An oscillatory behavior is observed in the indirect exchange coupling between the two ferromagnetic layers in sputtered ⟨111⟩ and ⟨100⟩ Ni81Fe19/Cu tCu/Ni81Fe19/Fe50Mn50spin valves. The periods of oscillations are 13.5 and 12.5 A˚ for the ⟨111⟩ and ⟨100⟩ growth directions, respectively. The coupling changes from strongly ferromagnetic, attCu=12 A˚, to antiferromagnetic attCu=9.5 A˚. At the transition region where the bilinear coupling changes sign (tCu≊10 A˚) biquadratic coupling is observed. The amplitude of the giant magnetoresistive effect reaches its maximum value fortCu=12 A˚, and values in excess of 4% are still observed fortCu=10 A˚. Interface sharpness is shown to be a key parameter for the observation of antiferromagnetic coupling, as well as a large magnetoresistive effect, at very thin copper layers. ©1996 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.361115

出版商:AIP    

年代:1996

数据来源: AIP