摘要:

Optically pumped lasing from InGaN/GaN single heterojunctions (SH) was observed in an edge emitting configuration at 77 K. The heterojunctions were grown by atmospheric pressure metalorganic chemical vapor deposition onc-plane sapphire substrates. The frequency tripled output of a mode-locked titanium:sapphire laser with a pulse width of 250 fs, operating at 280 nm, was used as the photoexcitation source. The nonlinear dependence of output emission intensity on input power density, the observations of a strongly polarized output emission, and distinct Fabry–Perot modes are discussed. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.364058

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Zr–Ce oxide films were made by reactive dc magnetron cosputtering. The elemental composition was determined by Rutherford backscattering spectrometery and the crystalline structure by x-ray diffraction. Li intercalation/deintercalation was accomplished potentiodynamically in a liquid electrolyte. The films remained fully transparent irrespective of their degree of lithiation, which may be reconciled with a population/depopulation of Ce4flevels. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.364059

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

In the Fe–Mo system, amorphous alloys are thermodynamically unstable and are hard to form in the bulk state. In multilayered films, however, amorphous alloys were produced by room temperature 200 keV xenon ion mixing. It was found, when keeping the total thickness of the multilayered film constant at 40 nm, that the composition range favoring amorphization extended from the equiatomic stoichiometry towards the two metal sides with increasing number of metal layers. This alloying behavior is discussed in terms of a simple thermodynamic calculation. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.364060

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We have developed a quantum mechanical model for understanding and explaining the capacitance–voltage (C–V) carrier profiles observed in quantum wells (QW). The external field imposed on the QW during C–V profiling changes the carrier distribution of the system. This model considers the effects of field and quantum confinement of the carriers in the well. The results obtained by iterative solutions of Schrodinger’s and Poisson’s equations give a better understanding of the experiments than the previous models where quantum confinement is ignored. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.364061

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Analyzing the photocurrent spectra and theI–Vcharacteristics of weakly coupled GaAs/AlGaAs multiquantum well structures, different transport regimes are distinguished. At low temperatures (below ∼50 K), due to the electron coherence over a few periods of the superlattice, electron transport is dominated by sequential resonant tunneling. At higher temperatures, evidences for the increased contribution of nonresonant transport processes, and the subsequent modification in the electric field distribution in the device, are presented. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.364062

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Alloy films of Co0.70Mn0.30were grown on GaAs (001) substrates by molecular beam epitaxy at room temperature. The metastable tetragonally distorted single crystal structure was confirmed by reflection high energy electron diffraction and x-ray diffraction measurement, which exhibited a 2.87 A˚ in-plane lattice parameter. Ferromagnetic resonance measurements and theoretical fitting were performed and showed that, with a Mn capping layer, a uni-directional anisotropy existed. In addition, a fourfold tetragonal magnetocrystalline anisotropy as well as a uniaxial term in the film plane was also confirmed. The hysteresis loops recorded by longitudinal magneto-optical Kerr-effect also demonstrated the existence of different kinds of in-plane magnetic anisotropy. The origins of the anisotropy are explained tentatively. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.364010

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

To understand the frequency dependence of phase transitions and related physical properties of Pb(Mg1/3Nb2/3)O3-based relaxor materials, the dielectric constants, electric-field-induced polarization, and pyroelectric depolarization are studied under varying temperatures and measuring frequencies. A linear relationship between the transition temperature and the logarithm of frequency is experimentally observed. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.364011

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

An expression of refractive indices for AlGaAs is presented which agrees reasonably with the experimental results by H. C. Casey Jr., D. D. Shell, and M. B. Panish [Appl. Phys. Lett.24, 63 (1974)]. This expression is approximately derived by using the method of least squares and is applicable to a determination of the refractive indices ofAlxGa1−xAswithxin the range0<x<0.38and for photon energy range between 1.2 and 1.8 eV. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.364443

出版商:AIP    

年代:1997

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.365557

出版商:AIP    

年代:1997

数据来源: AIP