摘要:

Variable‐energy positron annihilation depth‐profiling has been applied to the study of the Si/SiO2interface in Al‐gate metal‐oxide‐semiconductor (MOS) structures. For bothn‐ andp‐type silicon under conditions of negative gate bias, the positron annihilationS‐factor characteristic of the interface (Sint) is substantially modified. Temperature and annealing behavior, combined with known MOS physics, suggest strongly thatSintdepends directly on holes at interface states or traps at the Si/SiO2interface.

ISSN:0021-8979    

DOI:10.1063/1.350694

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

Successful fabrication of thin GaAs quantum wires (120–200 A˚)×(200–300 A˚) by a novel metal‐organic chemical‐vapor‐deposition growth technique is reported. The GaAs quantum wires were grown on a V groove formed by two GaAs triangular prisms which were selectively grown on SiO2masked substrates. The V groove has a very sharp corner at the bottom, which results in reduction of the effective width of the quantum wire structures. The measurement of photoluminescence and photoluminescence excitation spectra with polarization dependence indicate the existence of the quantized state in the quantum wires.

ISSN:0021-8979    

DOI:10.1063/1.350695

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

Having been exposed to hydrogen plasma, Te‐doped GaAs wafers were deposited with metal Ti, to form Ti/n‐GaAs Schottky barrier diodes (SBD). It was found that due to hydrogenation the Schottky barrier height (SBH) of the SBD decreases from 0.76 to 0.58 eV and the effective Richardson constantA** decreases from 11 to 0.03 A/cm2/K2. Annealing the hydrogenated SBD at different reverse biases at 100 °C produces SBHs that have a one‐to‐one correlation with the biases of reverse‐bias annealing (RBA), i.e., the SBH can be controlled, within the range 0.58–0.74 eV, by the bias of RBA. When the reverse bias is equal to or larger than 3 V, the SBH and the effective Richardson constant of the hydrogenated SBDs after RBA are very near to those of SBDs without hydrogenation. This means that a RBA with a bias higher than a critical value, 3 V in our case, can remove the effects of hydrogenation, but if the SBD is annealed again without a bias at 100 °C for 1 h or more, its SBH and effective Richardson constant recover their hydrogenated values. The main experimental facts can be explained qualitatively by a simple theoretical model.

ISSN:0021-8979    

DOI:10.1063/1.350696

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

In this work first room‐temperature photoluminescence in strained single and multiple quantum wells of InxGa1−xAs/GaAs grown by molecular‐beam epitaxy is presented. The In mole fractionxvaries from 0.06 to 0.23 and the well width from 5 to 20 nm. The data suggest that carrier generation in the well is caused by trapping carriers photoexcited in GaAs. The thermal behavior of this mechanism must be taken into account when the temperature dependence of the luminescence is analyzed.

ISSN:0021-8979    

DOI:10.1063/1.350697

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

Thin alloy films of Pd and Ni (8%<Ni<20% in at. %) formed by dual‐electron‐beam evaporation techniques have been found to give durable and quickly reversible detectors of high H2concentrations (pH20.1%–100%, 0.7–700 Torr) near 1 atm and 300 K, including accurate determinations ofpH2around the lower explosive limit of 4% in air. The addition of Ni suppresses the &agr; to &bgr; phase transition found in pure Pd under these conditions. The measurement of resistivity changes in the thin films along with flatband shifts of metal‐oxide‐semiconductor capacitors on the same Si wafer gives accurate values ofpH2over more than six decades.

ISSN:0021-8979    

DOI:10.1063/1.350646

出版商:AIP    

年代:1992

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.351409

出版商:AIP    

年代:1992

数据来源: AIP