摘要:

Resist patterning by scanning probe microscopy is a promising method to create structures in the nanometer range beyond the resolution of conventional electron beam or photo lithography. In conventional resist processing one has to remove either the exposed or unexposed resist in a solvent by an additional step. In this article we demonstrate the possibility of directly writing nano-scaled patterns in a thin amorphous carbon layer, which can be used as an etching mask, by a scanning force microscope. Above a threshold voltage between tip and sample small trenches can be created, whereby the carbon is completely removed from the exposed areas. Evidence is given that the mechanism responsible for the trench formation is a local field-induced oxidation of the carbon layer underneath the tip. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.366392

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Energies of basal-plane stacking faults in wurtzite AlN, GaN, and InN are determined using a one-dimensional Ising-type model incorporating effective layer–layer interactions obtained from density-functional-theory calculations. Stacking-fault energies are found to be largest for AlN and smallest for GaN consistent with density-functional results for the wurtzite/zinc-blende energy differences. Estimates are also given for stacking-fault energies in the zinc-blende structure. The values are negative, consistent with observations that nominal zinc-blende films typically contain large numbers of stacking faults. A related result is that hexagonal structures with stacking sequences repeating after four and six bilayers have lower energies than zinc-blende for all three compounds. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.366393

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

It is demonstrated that deep states in silicon on sapphire (SOS) films can be evaluated by transient-current spectroscopy (TCS). In the TCS spectra, a broad peak extending over 100–200 K was observed for the 6000-Å-thickn-type SOS film. Assuming the value of capture cross section to be10−15cm2and independent of temperature, the density distribution of deep states was estimated. The density distribution shows a peak of1.2×1012cm−2 eV−1atEC−0.25eV. Raman backscattering spectroscopy was also performed to evaluate the stress in the silicon film. It was concluded that the defects detected by TCS should be caused by the compressive stress of6.2×108Pa in the silicon film. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.366394

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We present an optical characterization technique to determine both the refractive index and the shrinkage of laterally oxidized AlAs and AlGaAs layers. The technique consists of measuring the angular dependence of the Fabry-Pe´rot dip wavelength in a simple cavity structure. Over standard ellipsometry, it has the advantage of measuring more realistic layer structures. Over transmission electron microscopy cross sections to determine the final aluminum-oxide layer thickness, it has the benefit of performing the measurement without elaborate sample preparation. We find that AlAs shrinks by approximately 3&percent; during oxidation, and that the refractive index of oxidized AlAs is 1.52. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.366395

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

A method previously developed for predicting the coupled magnetoelectric effect in a piezoelectric–piezomagnetic composite containing ellipsoidal inclusions is a general, explicit method and not as Huang and Kuo [J. Appl. Phys.81, 1378 (1997)] reviewed. After correcting two obvious mistakes in Huang and Kuo’s numerical results for effective coupled magnetoelectric coefficients, their results appear to be the same as one type of previous results. ©1997 American Institute of Physics. 

ISSN:0021-8979    

DOI:10.1063/1.366401

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The approach that we have adopted is fundamentally different from Nan’s, although the numerical results of both appear to be very similar. Using this approach, the resulting properties can be expressed in a rather simple form, without the need to evaluate the intermediate terms requiring additional calculations such as Nan’s Eqs. (28) and (29) [Phys. Rev. B50, 6082 (1994)]. For circular continuous fiber, for example, the use of our approach enables the magnetoelectric coupling coefficients to be expressed as&lgr;¯33=[2f(1−f)e31*q31]/[(1−f)(C12−C12*−C11*)−(1+f)C11],in which all terms involved are fundamental material constants. The influence of the material constants on the coupling coefficient can be readily understood. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.366544

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

It is shown that a previous comment on quantum well infrared photodetectors is not correct. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.366400

出版商:AIP    

年代:1997

数据来源: AIP