title: Extracting transport parameters in GaAs nanopillars grown by selective-area epitaxy.
abstract: We investigate the transport properties in p-type GaAs nanopillars (NPs) grown on GaAs(111) B substrates using selective-area epitaxy by studying single-NP field-effect transistors. Experimental results indicate that normalized resistance and field-effect mobility are highly sensitive to NP dimensions. Both in situ and ex situ chemical surface passivation techniques are found to significantly improve conductivity and mobility, especially for the smaller diameter NPs. A semi-empirical model based on diameter dependent mobility is used to extract actual doping levels and surface state density by fitting normalized resistance as a function of NP diameter. Surface state densities before and after passivation are found to be 5 × 10(12) cm(-2) eV(-1) and 7 × 10(10) cm(-2) eV(-1), respectively.
authors.affiliation: Department of Electrical Engineering, University of California at Los Angeles, CA 90095, USA. andrewlin@ucla.edu
authors.forename: Andrew
authors.initials: A
authors.lastname: Lin
authors.forename: Joshua N
authors.initials: JN
authors.lastname: Shapiro
authors.forename: Pradeep N
authors.initials: PN
authors.lastname: Senanayake
authors.forename: Adam C
authors.initials: AC
authors.lastname: Scofield
authors.forename: Ping-Show
authors.initials: PS
authors.lastname: Wong
authors.forename: Baolai
authors.initials: B
authors.lastname: Liang
authors.forename: Diana L
authors.initials: DL
authors.lastname: Huffaker