摘要:

Transmission electron microscopy was used to analyze the effects of annealing treatments on the morphologies of discontinuous gold films evaporated onto polystyrene or poly(2‐vinylpyridine) substrates. For polystyrene substrates the average size of discrete gold particles increases significantly during a long‐term annealing treatment at 179 °C. The size distribution is well approximated by a log normal distribution function, consistent with a coalescence mechanism for particle growth. The fluid character of the polymer substrates at the annealing temperature of interest allows us to control this coalescence rate, thereby providing a unique method for controlling the microstructure of discontinuous metal films. Cross‐sectional transmission electron microscopy showed that the coalescence rate for gold particles in a poly(2‐vinylpyridine) matrix is much less than the coalescence rate for gold particles in a polystyrene matrix, indicating that polymer/metal interactions play an important role in the determination of the coalescence rate.

ISSN:0021-8979    

DOI:10.1063/1.352362

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

An electron cyclotron resonance plasma using a circular TE01 mode microwave is generated to achieve larger diameters. It is shown that the input power of the circular TE01 mode is efficiently consumed to generate electron cyclotron resonance plasmas. The density and temperature of electrons is around 1012cm−3and 3–5 eV at 5 kW input power, respectively.

ISSN:0021-8979    

DOI:10.1063/1.352187

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

(100) oriented metal alloy films containing both body‐centered cubic (bcc) and face‐centered cubic (fcc) metals have been deposited on (100) Si using Pd/Cu seed layers. These include FeCo, FePt, FePd, FeCu, FeAu, FeAg, FeNi, VNi, and CrNi with different compositions. All the alloys show (200) spacings close to those of either the bcc or fcc component metals. To compare with Vegard’s rule, a correction factor of (1.5)1/2is needed between the fcc and bcc lattices, with the fcc spacing being 22% larger. Twenty alloy spacings are compared, assuming that both the lattice structures and spacings of the alloy films are mainly determined by the component metals whose spacings are close to those of the alloys. Good agreements with the Vegard’s rule are obtained for the thirteen (100) alloys with lattice spacings close to those of their respective bcc component metals, and for the seven (100) alloy films with lattice spacings close to their fcc component metals.

ISSN:0021-8979    

DOI:10.1063/1.352188

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

We have used nanoindentation to measure the mechanical properties of epitaxial TiN/(V0.6Nb0.4)N superlattices, grown on MgO(100), as a function of the wavelength &lgr;. The V/Nb ratio within the VNbN layers was chosen to provide a lattice match with TiN, minimizing effects resulting from coherency strains. For &lgr;≥4 nm, the hardness was found to be significantly enhanced relative to a homogeneous reference film of the same average composition. For &lgr;<4 nm, the hardness decreased to a value close to that of the reference film. The elastic modulus was found to be constant for &lgr;≥4nm, at a value close to that predicted by the law of mixtures. For samples with &lgr;=2.3 and 2.8 nm, there was a 15% decrease in modulus. The observed variations appear not to be an effect of interfacial strain. Possible mechanisms are discussed.

ISSN:0021-8979    

DOI:10.1063/1.352177

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

By varying the incident laser wavelength, the intrinsic Raman spectrum of porous silicon formed on nondegeneratep‐type silicon is identified and used to determine the dependence of the average pore size and porosity on the depth of the porous silicon layer. It is found that with increasing layer depth, the average pore size and porosity decreases, which is contrary to that of porous silicon formed on degeneraten‐type silicon. This may indicate a different formation mechanism for these two types of porous silicon.

ISSN:0021-8979    

DOI:10.1063/1.352178

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

A new method to get 413.7‐nm violet coherent radiation by using second‐harmonic generation and sum‐frequency mixing of radiation from a 1341.4‐ and 1079.5‐nm dual‐wavelength Nd:YALO3laser in a LiIO3crystal is reported in this communication. First, the 670.7‐nm red coherent radiation is obtained by second‐harmonic generation of 1341.4‐nm radiations in a LiIO3crystal, and then the 670.7‐ and 1079.5‐nm radiations are mixed again in a second LiIO3crystal to get 413.7‐nm radiation. The phase‐matching angles are obtained for both nonlinear optical processes. The experimental results agree well with calculated results.

ISSN:0021-8979    

DOI:10.1063/1.352179

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

For the first time tunnel junctions are prepared by a selective niobium etching process from Nb‐Al‐AlOx‐Al‐Nb sandwiches electron beam evaporated in ultrahigh vacuum. A quality factor ofVm=27 mV at 4.2 K has been obtained by cooling the Nb base electrode before Al deposition. The cooling of the Nb base layer had a considerable influence on the subgap current below 4.2 K. The temperature dependence of the subgap current down to 1.5 K is compared to the BCS prediction.

ISSN:0021-8979    

DOI:10.1063/1.352180

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

A compensation of stress induced in silicon epitaxial films heavily doped with boron was investigated. Addition of a controlled amount of germanium during the film growth allows one to attain a desired compressive or tensile stress in the film, or its complete elimination. The data shows very good correlation with a theoretical model adapted from Herzogetal. [J. Electrochem. Soc.131, 2969 (1984)]. A 6.45 : 1 ratio of atomic concentrations of Ge and B completely eliminates stress in these films. We determined a critical amount of strain in the films, &bartil;2–4 &mgr;m thick, beyond which misfit dislocations are generated.

ISSN:0021-8979    

DOI:10.1063/1.352181

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

The electronic structure of K2NiF4is calculated withabinitio, full potential and spin polarized pseudofunction energy band method. The bands are flat and have the indirect band gap of 0.7 eV between the occupied valence bands and empty conduction bands. The band gap is strongly influenced by the existence of [NiF6] crystal field and antiferromagnetic exchange interaction. Charge density plots show an anisotropic bonding between Ni and F in the basal plane and along the apical direction. Spin density plots exhibit an antiferromagnetic ordering with large localized moments on the Ni sites. However, a small fluctuation of net spin density is observed at the F sites. The computed optical conductivity is rather unremarkable with very small optically active structure. The salient features of our results are consistent with experimental observations.  

ISSN:0021-8979    

DOI:10.1063/1.352182

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

The ‘‘analysis of microelectronic and photonic structures’’ (amps) transport‐simulation computer program has been used to show that a distinction can be made between the effects of light‐induced bulk and interfacial degradation in hydrogenated amorphous silicon (a‐Si:H)p‐i‐ndetector and solar cell structures. Using reverse bias leakage (dark) currents,ampssimulations show that, forpandnlayers that do not allow significant injection of electrons and holes into the intrinsic layer of thep‐i‐nstructure, a light‐induced increase in the density of interfacial states will result in significantly different changes in the voltage behavior of the reverse bias dark currents than will a corresponding increase in the density of bulk defect states. This communication demonstrates that a careful study of the reverse bias dark currents can provide an excellent means of determining if light soaking ofa‐Si:Hp‐i‐ndevices results in bulk degradation, interfacial degradation, or both.

ISSN:0021-8979    

DOI:10.1063/1.352337

出版商:AIP    

年代:1992

数据来源: AIP