Electron Transport Properties in a GaAs/AlGaAs Quantum Wire Grown on V-Grooved GaAs Substrate by Metalorganic Vapor Phase Epitaxy

概要

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A series of nonlinear conductance phenomena is investigated in the GaAs V-grooved quantum wire (QWR) field effect transistors (FETs) prepared by the flow-rate modulated epitaxy (FME) technique. These are attributed to Coulomb blockade at a subthreshold gate bias, universal conductance steps near the threshold, real space transfer under a forward gate bias and a large source-drain bias condition. Weak carrier coupling between sidewall quantum wells and QWR is responsible for the small step height of the measured universal conductance ($G_{\text{m}}\ll G_{0}=2e^{2}/h$). Shubnikov de Haas oscillation measurements revealed that sidewall quantum wells in the V-groove quantum wire act as additional current paths and are switched or mixed with QWR depending on the gate bias conditions and device geometry. The gate-bias-dependent current path switching is found to be responsible for the large current steps and negative differential resistance (NDR) in the drain current ($I_{\text{DS}}$)-gate bias ($V_{\text{GS}}$) and $I_{\text{DS}}$-drain bias ($V_{\text{DS}}$) relationships, respectively.
2003-04-15