摘要:

Optical gain in quantum wire (QWI) lasers are theoretically investigated as functions of wire crystallographic direction taking valence band anisotropy into account. Calculations for GaAs cylindrical QWI with infinite barriers are performed by using the 4×4 Luttinger–Kohn Hamiltonian. Considering the structural optimization of QWI lasers from the viewpoint of crystallographic direction, we find that a [111]‐QWI lasers is the most suitable low‐threshold laser and that a [1,−1,0]‐QWI laser on a (110) substrate is the most suitable polarization‐stab‐ilized vertical‐cavity surface‐emitting laser. ©1996 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.361235

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

The elastic constants of GaN have been determined using Brillouin scattering; in GPa they are:C11=390,  C33=398,  C44=105,  C66=123,  C12=145,  and   C13=106. Our values differ substantially from those quoted in the literature which were obtained from the determination of mean square displacement of atoms measured by x‐ray diffraction. ©1996 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.361236

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

The strain‐induced periodical domain inversion in KTiOPO4(KTP) has been demonstratedinsituby means of the nonlinear light diffraction. The temperature of 730 °C was found to be the starting point of the opposite sign domains growth under the heating of −ZKTP substrate (rate 70 °C/s) with the periodical SiO2mask. The depth of the fabricated domain‐reversed structure of the 5.5 &mgr;m period was measured to be 4.5 &mgr;m. ©1996 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.361237

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

A fabrication method using a metal‐covered scanning tunneling microscope tip has been developed to provide a nanoscale deposition method with various metal species. Nanoscale deposition has been carried out on highly oriented pyrolytic graphite with a core tungsten tip, a gold‐covered tungsten tip, and an aluminum‐covered tungsten tip, by applying tip positive voltage pulses. The threshold voltage, above which deposition occurred, showed a linear dependence on the tip‐sample separation and differed for tip material. This suggests that the fabrication mechanism is field‐induced and the deposition takes place by the transfer of tip material to the sample. ©1996 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.361238

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

We present a self‐consistent calculation of the electronic structure ofp‐type delta‐doped quantum wells in GaAs. We examine the dependence of the energy levels, Fermi level and the depth of the well with impurity concentration. We show that in this system the Fermi level is very close to the valence band; the heavy‐hole subbands, as expected, contain many more states than the light‐hole ones. Our results agree quite well with the experimental results available for this system. ©1996 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.361239

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

Lasing has been obtained near 2.6 &mgr;m in double‐heterostructure InGaAs/InAlAs diode lasers grown by metalorganic vapor phase epitaxy on InAs substrates. At 80 K threshold currents are in the range of 40–200 mA for lasers of deep mesa geometry. The characteristic temperature of the temperature dependence of the threshold currentT0is 21–23 K and lasing was achieved up to 150 K in a pulsed regime. A blueshift of up to 3.0 nm with increasing current is observed. A blueshift is also observed with increasing temperature, which is attributed to refractive index change due to the strong temperature dependence of the threshold carrier density in narrow gap III–V semiconductor lasers. ©1996 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.361240

出版商:AIP    

年代:1996

数据来源: AIP