Novel Quantum Wire Branch-Switches for Binary Decision Diagram Logic Architecture Utilizing Schottky Wrap-Gate Control of GaAs/AlGaAs Nanowires

摘要

A novel binary decision diagram (BDD) node device based on wrap-gate (WPG) control of AlGaAs/GaAs nanowires is described and fabricated, and its basic operation is characterized. The node device consists of one entry-nanowire branch and two exit-nanowire branches where each of two exit-branches is switched by a Schottky WPG in a complimentary fashion so as to realize path switching for electrons. Basic branch switches as well as BDD node devices were fabricated on AlGaAs/GaAs nanowires formed by electron beam lithography and wet chemical etching of molecular beam epitaxy (MBE)-grown heterostructures. A detailed analysis of gate control characteristics was carried out by magneto tran sport measurements. A three-dimensional potential simulation showed that Fermi level pinning on the semiconductor free surface should be carefully taken into consideration for accurate device design. The branch-switch exhibited excellent gate control from low temperatures up to room temperature. showing clear conductance quantization at low temperatures, The fabricated BDD node device realized clear path switching from low temperatures up to room temperature.