Carrier Lifetime and Mobility Enhancement in Nearly Defect-Free Core−Shell Nanowires Measured Using Time-Resolved Terahertz Spectroscopy
journal contributionposted on 2009-09-09, 00:00 authored by Patrick Parkinson, Hannah J. Joyce, Qiang Gao, Hark Hoe Tan, Xin Zhang, Jin Zou, Chennupati Jagadish, Laura M. Herz, Michael B. Johnston
We have used transient terahertz photoconductivity measurements to assess the efficacy of two-temperature growth and core−shell encapsulation techniques on the electronic properties of GaAs nanowires. We demonstrate that two-temperature growth of the GaAs core leads to an almost doubling in charge-carrier mobility and a tripling of carrier lifetime. In addition, overcoating the GaAs core with a larger-bandgap material is shown to reduce the density of surface traps by 82%, thereby enhancing the charge conductivity.