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Double Barrier Resonant Tunneling Transistor with a Fully Two Dimensional Emitter

Description: A novel planar resonant tunneling transistor is demonstrated. The growth structure is similar to that of a double-barrier resonant tunneling diode (RTD), except for a fully two-dimensional (2D) emitter formed by a quantum well. Current is fed laterally into the emitter, and the 2D--2D resonant tunneling current is controlled by a surface gate. This unique device structure achieves figures-of-merit, i.e. peak current densities and peak voltages, approaching that of state-of-the-art RTDs. Most importantly, sensitive control of the peak current and voltage is achieved by gating of the emitter quantum well subband energy. This quantum tunneling transistor shows exceptional promise for ultra-high speed and multifunctional operation at room temperature.
Date: July 13, 2000
Creator: MOON,J.S.; SIMMONS,JERRY A.; RENO,JOHN L.; BACA,WES E.; BLOUNT,MARK A.; HIETALA,VINCENT M. et al.
Partner: UNT Libraries Government Documents Department

Magnetic Anticrossing of 1D Subbands in Coupled Ballistic Double Quantum Wires

Description: We study the low-temperature in-plane magnetoconductance of vertically coupled double quantum wires. Using a novel flip-chip technique, the wires are defined by two pairs of mutually aligned split gates on opposite sides of a s 1 micron thick AlGaAs/GaAs double quantum well heterostructure. We observe quantized conductance steps due to each quantum well and demonstrate independent control of each ID wire. A broad dip in the magnetoconductance at -6 T is observed when a magnetic field is applied perpendicular to both the current and growth directions. This conductance dip is observed only when 1D subbands are populated in both the top and bottom constrictions. This data is consistent with a counting model whereby the number of subbands crossing the Fermi level changes with field due to the formation of an anticrossing in each pair of 1D subbands.
Date: July 13, 2000
Creator: BLOUNT,MARK A.; MOON,JEONG-SUN; SIMMONS,JERRY A.; LYO,SUNGKWUN K.; WENDT,JOEL R. & RENO,JOHN L.
Partner: UNT Libraries Government Documents Department

Magnetoconductance of Independently Tunable Tunnel-Coupled Double Quantum Wires

Description: The authors report on their recent experimental studies of vertically-coupled quantum point contacts subject to in-plane magnetic fields. Using a novel flip-chip technique, mutually aligned split gates on both sides of a sub micron thick double quantum well heterostructure define a closely-coupled pair of ballistic one-dimensional (1D) constrictions. They observe quantized conductance steps due to each quantum well and demonstrate independent control of each ID constriction width. In addition, a novel magnetoconductance feature at {approximately}6 T is observed when a magnetic field is applied perpendicular to both the current and growth directions. This conductance dip is observed only when 1D subbands are populated in both the top and bottom constrictions. This data is consistent with a counting model whereby the number of subbands crossing the Fermi level changes with field due to the formation of an anticrossing in each pair of 1D subbands.
Date: July 13, 2000
Creator: BLOUNT,MARK A.; MOON,J.S.; SIMMONS,JERRY A.; LYO,SUNGKWUN K.; WENDT,JOEL R. & RENO,JOHN L.
Partner: UNT Libraries Government Documents Department