An indirect method to determine the internal polarization of a GaN/AlGaN-based quantum well is presented. The technique consists of carefully measuring the difference between the two lowest conduction subband levels under the application of an electrical bias across the epitaxial layers. Due to a quantum confined Stark effect, the bound energy levels of the well show a strong frequency shift, which depends on the size of the external field. Since this electric field was oriented oppositely to the internal polarization, partial screening of the latter occurred. By measuring these Stark shifts at three different fields, one was able to calculate the size of the internal polarization. Since the composition of the AlGaN barriers had previously been determined by X-ray diffraction, an extrapolated value of the internal polarization-as it would occur in a pure AlN/GaN interface-could be given. In agreement with the literature, a value of 720 MV/m was found.

Sylwester Porowski, Bulk and Homoepitaxial GaN-growth and Characterisation, Journal of Crystal Growth, 1998, 153–158, 189/190, Elsevier Science B.V., Warsaw, Poland. Y. Naoi. K. Kobatake, S. Kurai, K. Nishino, H. Sato, M. Nozaki, S. Sakai, Y. Shintani, Characterization of bulk GaN grown by Sublimation technique, Journal of Crystal Growth, 1998, 163–166, 189/190, Elsevier Science B.V., Warshaw, Poland.

PROBLEM TO BE SOLVED: To provide a method and apparatus for obtaining an electronic substrate having a plurality of semiconductor devices.SOLUTION: A nanowire thin film is formed on a substrate. The nanowire thin film is formed to have sufficient density of nanowires to achieve operating current level. A plurality of semiconductor regions are defined in the nanowire thin film. Contacts are formed in the semiconductor device area, thereby providing electrical connections to a plurality of semiconductor devices. In addition, various materials for manufacturing nanowires, thin films including p-type doped nanowires and n-type doped nanowires, nanowire heterostructures, luminescent nanowire heterostructures, flow masks for placing nanowires on substrates, techniques for spraying nanowires to deposit nanowires, techniques for reducing or eliminating phonon scattering of electrons in nanowires, and techniques for reducing surface states in nanowires are described.SELECTED DRAWING: None

Low-ridge-configuration, quantum-cascade lasers operating at 5.3 mum provide, at 80 K, 12 W peak-pulsed power at 14 A drive. A model of current spreading that takes into account the lateral variation in transverse conductivity adequately explains the results.

A low-voltage, 90-nm CMOS optical interconnect transceiver operating at 1550-nm optical wavelength is presented. This is the first demonstration of a novel optoelectronic modulator architecture (the quasi-waveguide angled-facet electroabsorption modulator) in a system. It features a simple electronic packaging via flip-chip bonding to silicon. Devices have a broad optical bandwidth, are arrayed two dimensionally, and feature surface normal, spatially separated, and misalignment-tolerant optical ports. The modulators are driven with a novel pulsed-cascode driver capable of supplying an output-voltage swing of 2 V (twice the nominal 1-V CMOS supply) without overstressing thin-oxide core CMOS devices. At the receiver side, a sensitivity of -15.2 dBm is obtained with an integrating/double-sampling front end. The transceiver includes clock generation and recovery circuitry that enables a data serialization factor of five. At a maximum data rate of 1.8 Gb/s, the optical transmitter, receiver, and clocking circuitry consume 12.6, 4.5, and 6.5 mW, respectively, for a total link electrical power dissipation of 23.6 mW. To the best of our knowledge, this is the first demonstration of an interconnect transceiver operating at 1550 nm with a III-V output device directly integrated to the CMOS.

A low-voltage 90 nm CMOS optical interconnect transceiver operating at 1550 nm is presented. This is the first system demonstrated using the recent quasi-waveguide angled facet electroabsorption modulator (QWAFEM), featuring simple electronic and optical packaging.

L'invention concerne des procedes de dopage de nanostructures, telles que des nanofils. Ces procedes permettent d'engendrer diverses approches d'amelioration de procedes existants de dopage de nanostructures. Les modes de realisation comprennent l'utilisation d'une couche sacrificielle afin de favoriser une distribution de dopant uniforme au sein d'une nanostructure pendant le dopage de synthese post-nanostructure. Dans un autre mode de realisation, un environnement de temperature elevee est utilise pour recuire les dommages occasionnes a la nanostructure, lorsqu'est utilisee une implantation ionique d'energie elevee. Dans un mode de realisation distinct, un recuit thermique rapide est utilise pour amener des dopants d'une couche de dopant sur une nanostructure jusque dans ladite nanostructure. Dans un mode de realisation different, un procede de dopage de nanofils sur un substrat plastique permet de deposer un empilement dielectrique sur un substrat plastique afin de proteger le substrat plastique des dommages se produisant pendant le processus de dopage. Un mode de realisation a trait a l'utilisation selective de concentrations elevees de matieres dopantes a divers moments dans la synthese de nanostructures, afin de realiser de nouvelles structures cristallographiques au sein de la nanostructure resultante.