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The role of spontaneous and piezoelectric polarization in III–V nitride heterostructures is investigated. Polarization effects and crystal polarity are reviewed in the context of nitride heterostructure materials and device design, and a detailed analysis of their influence in nitride heterostructure field-effect transistors is presented. The combined(More)
Electron concentration profiles have been obtained for Al x Ga 1Ϫx N/GaN heterostructure field-effect transistor structures. Analysis of the measured electron distributions demonstrates the influence of piezoelectric effects in coherently strained layers on III-V nitride heterostructure device characteristics. Characterization of a nominally undoped Al 0.15(More)
Deep-level transient spectroscopy has been used to characterize electronic defects in n-type GaN grown by reactive molecular-beam epitaxy. Five deep-level electronic defects were observed, with activation energies E 1 ϭ0. are interpreted as corresponding to deep levels previously reported in n-GaN grown by both hydride vapor-phase epitaxy and metal organic(More)
A method for enhancing effective Schottky barrier heights in III–V nitride heterostructures based on the piezoelectric effect is proposed, demonstrated, and analyzed. Two-layer GaN/Al x Ga 1Ϫx N barriers within heterostructure field-effect transistor epitaxial layer structures are shown to possess significantly larger effective barrier heights than those(More)
Vertical and electrically isolated InAs nanowires ͑NWs͒ are integrated with Si in a technique that bypasses structural defects and transport barriers at the Si–III–V NW interface. Smart-cut® technique is used to transfer a thin InAs layer onto SiO 2 / Si and is subsequently used for ordered organometallic vapor phase epitaxy of InAs NWs. The InAs layer in(More)
The technique of transferring patterned ion-cut layers from one Si wafer to another was demonstrated. The starting silicon wafer was masked with checkerboard and line patterns with a 3 ␮m thick polymethylmethacrylate/photoresist and was implanted with 5ϫ10 16 H ϩ ions/cm 2 at 150 keV. After stripping off the mask, the wafer was bonded to an oxide-coated(More)
A common understanding in sustainable urban development is to promote high dense, mixed used and walkable living districts to minimize energy consumption and pollution, create a liveable environment and enhance social interaction (Calthorpe, 1993). Through last a few decades, research findings have confirmed that both community characters and spatial forms,(More)
Survival and respiration rates of the bacterial-feeding nematode Cruznema tripartitum after incubation in soil for 48 hr provided a useful bioassay of the presence and concentration level of biologically active toxicants. The assay provided an indication of toxicant activity at sublethal levels, and a means of determining when the toxicant had declined to(More)
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