TRANSPORT CHARACTERIZATION OF INPLANE GATE DEVICES FABRICATED BY DIRECT EPITAXIAL-GROWTH ON PATTERNED SUBSTRATES

Direct molecular-beam epitaxial growth of GaAs/AlxGa1-xAs heterostruct ures on bow-tie shaped constrictions, prepatterned on GaAs substrates is used to fabricate in-plane gate transistors. The fabricated devices can be tuned by applying voltages to in-plane gates, which are also r ealized during the epitaxial growth. In this way, complete in-plane ga te transistors are fabricated in a single growth process, Transport me asurements of the devices at 1.3 K show conductance quantization or Co ulomb blockade depending on the width of the constriction. The Coulomb blockade effect in the narrowest structures is caused by the formatio n of a self-assembled quantum dot in the center of the constriction. ( C) 1996 American Institute of Physics.