Elemental and electrical characterization of thin SiO2 films deposited downstream from a microwave discharge AIP Conf.

Time-resolved radiative recombination measurements on GaSb quantum dots have been performed. The GaSb quantum dots are grown by molecular beam epitaxy on ͑100͒ GaAs through a self-assembly process. Time-resolved measurements show that, after a rapid hole capture process, the photoluminescence decays with a fast and a slow component. The fast component is shortened significantly with higher excitation intensity while the slow component is roughly constant. The radiative lifetimes are much longer than the lifetimes of ordinary GaSb quantum wells with a straddling band lineup. These results support a staggered band lineup and space charge induced band-bending model.

We have experimentally extracted the virtual-source electron injection velocity, v x0 , of various III-V HFETs at room temperature. This is the carrier velocity that matters for logic applications of these transistors. Sub-100 nm devices with μ n > 10,000 cm 2 /V-s exhibit v x0 in excess of 3 × 10 7 cm/s even at V DD = 0.5 V. This is over 2 times that of state-of-the-art Si devices at V DD > 1. We have verified our extraction methodology for v x0 by building a simple charge-based semiempirical model for the I-V characteristics of III-V HFETs. This model yields an excellent description of the entire I-V characteristics of the devices from subthreshold to inversion and from linear to saturation regimes with fitted electron velocities that are very close to those independently obtained through our proposed extraction methodology.

We present magnetotransport experiments on high-quality InAs-AlSb quantum wells that show a perfectly clean single-period Shubnikov-de Haas oscillation down to very low magnetic fields. In contrast to theoretical expectations based on an asymmetry induced zero-field spin splitting, no beating effect is observed. The carrier density has been changed by the persistent photo conductivity effect as well as via the application of hydrostatic pressure in order to influence the electric field at the interface of the electron gas. Still no indication of spin splitting at zero magnetic field was observed in spite of highly resolved Shubnikov- de Haas oscillations up to filling factors of 200. This surprising and unexpected result is discussed in view of other recently published data.Comment: 4 pages, 3 figures, submitted to Phys. Rev.

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