Friday, October 20, 2017

Abstract-Investigations of doping via optical pump terahertz-probe spectroscopy


 Jessica L. Boland,   A. Casadei,   G. Tütüncouglu,  F. Matteini , C. Davies,  F. Gaveen, F. Amaduzzi,   H.J. Joyce,  L.M. Herz,   A. Fontcuberta i Morral,  Michael B. Johnston

http://ieeexplore.ieee.org/document/8066895/

Reliable doping in semiconductor nanowires is essential for the development of novel optoelectronic devices. Dopant incorporation within the nanowire can allow for optimisation of key optoelectronic properties, such as electron mobility and carrier lifetime. Thus, in-depth characterisation of doping mechanisms in semiconductor nanowires and their effect on the nanowire optoelectronics properties is crucial. However, extraction of the dopant concentration by conventional electrical methods remains difficult due to the associated challenges with fabricating lateral contacts onto the nanowire. In this work, we present a non-contact technique based on optical pump terahertz-probe spectroscopy for examining the extrinsic carrier concentration and optoelectronic properties of semiconductor nanowires. By extracting the temperature-dependent charge carrier dynamics, we show for the first time that the dopant activation energy and underlying scattering mechanisms affecting charge carrier mobility in these nanostructures can be determined via terahertz spectroscopy.

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