摘要:

We investigate the near field distribution of light diffracted from deep grooves of sub-wavelength lateral dimensions, carved on a flat metallic surface. It is shown that, in spite of multiple interaction, the reflected field presents, forspolarization, peaks very localized on the groove positions, and whose amplitude increases with the groove depth. Forppolarization, however, the near field does not follow the surface profile. This permits us to establish forspolarization a threshold in order to distinguish signals produced on reflection from grooves having different profiles. This is of guidance in diffractive modeling of readout systems of high density optical disks. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119295

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The absorption spectra are reported for isolated Se andHgI2semiconductor chains accommodated inAlPO4-5 (AFI) channels of diameter 7.3 Å. The lowest electronic excitation states of the isolated chains are shifted to higher energy from the band edge transitions of their bulk crystals. The blue shifts are qualitatively explained by the quantum confinement effects of carriers in a one-dimensional wire. The experimental result of the Se/AFI is in good agreement with the theoretical expectation based on the effective-mass-approximation. The result of theHgI2/AFI, however, does not agree with the calculation. The different behaviors of the Se/AFI and theHgI2/AFI are expected to result from their different electronic structures. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119296

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The effects of fluorine on ultrathin gate oxide and oxynitride (∼40 Å) have been studied. The incorporation of fluorine was done by fluorine ion implantation into polycrystalline silicon (polysilicon) gate followed by a high-temperature drive-in step. It has been found that the integrity of oxide has been improved with the incorporation of fluorine as demonstrated by the reduction of stress-induced leakage current and interface trap generation. Furthermore, unlike thicker dielectrics (>100 Å) for which the charge-to-breakdown (QBD)values decrease with increasing fluorine concentration,QBD’s remain the same as those of the control samples for the ultrathin thickness regime. The mechanism for oxide quality improvement by F will also be discussed in the letter. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119297

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We report metal–organic chemical-vapor deposition-grown double heterostructure InAsSbP/InAsSb/InAs diode lasers emitting at 3.2 &mgr;m operating at temperatures up to 220 K with threshold current density of 40A/cm2at 77 K and characteristic temperature up to 42 K. Output powers as high as 260 mW in pulse mode and 60 mW in continuous wave operation have been obtained from an uncoated 100 &mgr;m stripe-width broad-area laser at 77 K. Comparison with theory shows that there is no significant nonradiative recombination mechanism for these lasers at 77 K. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119298

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We have developed a new thin-film differential scanning calorimetry technique that has extremely high sensitivity of 0.2 nJ. By combining two calorimeters in a differential measurement configuration, we have measured the heat capacity and melting process of Sn nanostructures formed via thermal evaporation with deposition thickness down to 1 Å. The equivalent resolution of the calorimeter is 1 nanogram in mass or 0.4 Å in thickness. We have observed a decrease of up to 120°C in the melting point of Sn nanostructures. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119299

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

(Pb0.97La0.03)(Zr0.66Ti0.34)0.9875O3, PLZT, thin films deposited on eitherLaNiO3(LNO) or LNO/Pt coatedSi3N4/Sisubstrates, possessing good ferroelectric properties, were successfully obtained by the pulsed laser deposition process. Using LNO/Pt as double layer electrodes not only resulted in PLZT films with superior electric properties, but also of better handling endurance. The former is attributed to the low surface resistivity of electrode materials (i.e.,&rgr;LNO/Pt=0.5m&OHgr; cm) due to the bypassing effect of the Pt layer, whereas the latter is ascribed to the induction of compressive stress on PLZT and LNO layers due to a relatively larger thermal expansion coefficient (CTE) of the Pt layer. The ferroelectric properties of(PLZT )LNO/ptfilms werePr=16.5&mgr;C/cm2andEc=63.5kV/cm, while the dielectric constant and leakage current wereK=1.028andJe⩽8×10−6A/cm2(under 150 kV/cm), respectively. Their fatigue life was longer than2×109cycles under action of 300 kV/cm pulse. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119300

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We report on the molecular beam epitaxial growth of Ge on Si(110) surfaces. High temperature cleaning (oxide desorption) results in the formation of shallow faceted pits distributed randomly on the Si(110) surface. Deposition of Ge at temperatures between 600 and 725 °C leads to preferential nucleation along the pit edges forming elongated islands, which subsequently grow to compact three-dimensional coherent islands. The observation of strained islands in close proximity to each other offers insights into their nucleation behavior and strain relaxation. Our observations suggest heterogeneous nucleation as a possible method for fabricating assemblies of quantum dots. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119301

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Critical interdependent effects have been observed in the growth of AlGaAs/InGaAs quantum-well structures by molecular beam epitaxy. It is shown that statistical experimental design is an effective method for quickly optimizing complex device structures. This technique is very useful for the optimization of processes with a large number of interdependent parameters, and allows for the clear visualization and separation of complex interwoven effects. In the present work, we show the importance of the oxide desorption process for the optimal growth of AlGaAs-containing structures. ©1997 American Institute of Physics. 

ISSN:0003-6951    

DOI:10.1063/1.119303

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

A novel and simple method to suppress the boron penetration in theBF2+-implanted polycrystalline silicon gate is presented by using the inductive-coupling-nitrogen-plasma (ICNP) process. A nitrogen layer was found at theSiO2/Siinterface by using this method. The result shows that the sample with the ICNP treatment exhibits a good suppression of boron penetration and improved electrical characteristics. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119304

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We report on a study of Al and Ti/Al contacts ton-type GaN. Al contacts onn-GaN(7×1017 cm−3)annealed in forming gas at 600 °C reached a minimum contact resistivity of8×10−6 &OHgr; cm2and had much better thermal stability than reported by previous researchers. Ti/Al (35/115 nm) contacts onn-GaN(5×1017 cm−3)had resistivities of7×10−6and5×10−6 &OHgr; cm2after annealing in Ar at 400 °C for 5 min and 600 °C for 15 s, respectively. Depth profiles of Ti/Al contacts annealed at 400 °C showed that low contact resistance was only achieved after Al diffused to the GaN interface. We propose that the mechanism for Ohmic contact formation in Ti/Al contacts annealed in the 400–600 °C range includes Ti reducing the GaN native oxide and an Al–Ti intermetallic coming into intimate contact with the GaN. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119305

出版商:AIP    

年代:1997

数据来源: AIP