Compact Reconfigurable Binary-Decision-Diagram Logic Circuit on a GaAs Nanowire Network

We describe a reconfigurable binary-decision-diagram logic circuit based on Shannon's expansion of Boolean logic function and its graphical representation on a semiconductor nanowire network. The circuit is reconfigured by using programmable switches that electrically connect and disconnect a small number of branches. This circuit has a compact structure with a small number of devices compared with the conventional look-up table architecture. A variable Boolean logic circuit was fabricated on an etched GaAs nanowire network having hexagonal topology with Schottky wrap gates and SiN-based programmable switches, and its correct logic operation together with dynamic reconfiguration was demonstrated.

Spin-Polarized Localized Exciton Photoluminescence Dynamics in GaInNAs Quantum Wells

We have investigated spin polarization-related localized exciton photoluminescence (PL) dynamics in GaInNAs quantum wells by time-resolved PL spectroscopy. The emission energy dependence of PL polarization decay time as well as polarization-independent PL decay time suggests that the acoustic phonon scattering in the process of localized exciton transfer from the high-energy localized states to the low-energy ones dominates the PL polarization relaxation. By increasing the excitation power from 1 to 10 mW, the PL polarization decay time is changed from 0.17 to more than 1 ns, which indicates the significant effect of the trapping of localized electrons by nonradiative recombination centers. These experimental findings indicate that the spin-related PL polarization in diluted nitride semiconductors can be manipulated through carrier scattering and recombination process. (C) 2009 The Japan Society of Applied Physics