Transport characterization of in-plane gate devices fabricated by direct epitaxial growth on patterned substrates

Abstract

Direct molecular-beam epitaxial growth of GaAs/AlxGa1−xAs heterostructures 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 realized during the epitaxial growth. In this way, complete in-plane gate transistors are fabricated in a single growth process. Transport measurements of the devices at 1.3 K show conductance quantization or Coulomb blockade depending on the width of the constriction. The Coulomb blockade effect in the narrowest structures is caused by the formation of a self-assembled quantum dot in the center of the constriction.