The magnetoresistance at temperatures below 20 K in an n-InSb/ In 0.85 Al 0.15 Sb two-dimensional electron system is studied and described in terms of antilocalization due to quantum interference under strong spin-orbit interaction. The spin-orbit interaction coefficients are extracted by fitting the magnetoresistance data to an antilocalization theory distinguishing the Rashba and Dresselhaus contributions. A good agreement between magnetoresistance data and theory suggests a Rashba coefficient ͉␣͉Ϸ0.03 eV Å and a Dresselhaus coefficient ␥ Ϸ 490 eV Å 3 . A strong contribution from the Dresselhaus term leads to pronounced anisotropy in the energy splitting induced by spin-orbit interaction in the two-dimensional electron dispersion.

The relationship between crystal quality and the properties of indium phosphide nanowires grown on silicon (111) has been studied by transmission electron microscopy, photoluminescence spectroscopy, and photoelectrochemistry. Wires with no defects and with {111} twin boundaries parallel and perpendicular to the growth direction were obtained by metalorganic vapor-phase epitaxy using liquid indium catalyst. Room temperature photoluminescence from the defect-free nanowires is approximately 7 times more intense than that from the wires with twin boundaries. An open-circuit photovoltage of 100 mV is observed for photoelectrochemical cells made with the defect-free nanowires, whereas no photovoltage is recorded for those with twins.

The morphological phase diagram is reported for InP nanostructures grown on InP (111)B as a function of temperature and V/III ratio. Indium droplets were used as the catalyst and were generated in situ in the metalorganic vapor-phase epitaxy reactor. Three distinct nanostructures were observed: wires, cones, and pillars. It is proposed that the shape depends on the relative rates of indium phosphide deposition via the vapor-liquid-solid (VLS) and vapor-phase epitaxy (VPE) processes. The rate of VLS is relatively insensitive to temperature and results in vertical wire growth starting at 350 degrees C. By contrast, the rate of VPE accelerates with temperature and drives the lateral growth of cones at 385 degrees C and then pillars at 400 degrees C.

A mesoscopic nonmagnetic magnetoresistive read-head sensor based on the recently reported extraordinary magnetoresistance (EMR) effect has been fabricated from a narrow-gap Si-doped InSb quantum well. The sensor has a conservatively estimated areal-density of 116 Gb/in.2 with a 300 K EMR of 6% and a current sensitivity of 147 Ω/T at a relevant field of 0.05 T and a bias of 0.27 T. Because this sensor is not subject to magnetic noise, which limits conventional sensors to areal densities of order 100 Gb/in.2, it opens a pathway to ultra-high-density recording at areal densities of order 1 Tb/in.2.

Vertical indium phosphide nanowires have been grown epitaxially on silicon (111) by metalorganic vapor-phase epitaxy. Liquid indium droplets were formed in situ and used to catalyze deposition. For growth at 350 degrees C, about 70% of the wires were vertical, while the remaining ones were distributed in the 3 other <111> directions. The vertical fraction, growth rate, and tapering of the wires increased with temperature and V/III ratio. At 370 degrees C and V/III equal to 200, 100% of the wires were vertical with a density of approximately 1.0 x 10(9) cm(-2) and average dimensions of 3.9 mum in length, 45 nm in base width, and 15 nm in tip width. X-ray diffraction and transmission electron microscopy revealed that the wires were single-crystal zinc blende, although they contained a high density of rotational twins perpendicular to the <111> growth direction. The room temperature photoluminescence spectrum exhibited one peak centered at 912 +/- 10 nm with a FWHM of approximately 60 nm.

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The influence of various process conditions on the structural integrity and electrical properties of Al∕HfO2∕p-In0.13Ga0.87As metal-oxide-semiconductor capacitors was investigated. Room temperature capacitance voltage measurements revealed postdielectric deposition anneal reduced hysteresis by more than 0.5V and sulfur passivation of InGaAs improved the capacitance frequency dispersion properties as well as reduced interface trap density. At V=VFB−1V, the leakage current densities ∼1.3×10−7, 0.4×10−6, and 1.3×10−6A∕cm2 were measured in devices with annealed HfO2 (110 and 32Å) and sulfur-passivated InGaAs (110Å unannealed HfO2), respectively. Transmission electron microscopy revealed sharp epitaxial InGaAs/crystalline HfO2 and GaAs∕InGaAs interfaces.

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