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Title: Near-field photocurrent characterisation of semiconductor devices
Author: Ackland, M. P.
Awarding Body: University of Wales Swansea
Current Institution: Swansea University
Date of Award: 2005
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A near-field scanning optical microscope (NSOM) has been modified to perform near-field photocurrent imaging via the development and implementation of a two-stage amplification/detection scheme. The near-field photocurrent imaging capability has been employed along with simultaneous topographic image acquisition in the analysis of the buried Schottky interface of nickel-silicon carbide (Ni-SiC) Schottky contacts. Silicon carbide is stable at high temperatures and operating powers and thus could fulfil a wide range of potential applications, however in order to implement SiC devices in such applications stable metal contacts are a necessity and remain a field requiring optimisation. Near-field photocurrent imaging has directly imaged the buried interface properties and lateral variations in the Schottky barrier energy on the nanoscale, which have been related to the macroscopic electrical characteristics of the Schottky contact. The Schottky barrier energy has been increased by 0.155eV via annealing at 500°C, this resulted in an increase in the lateral variation in barrier properties, as reflected in the ideality factor increase of 0.3, and similarly recorded by near-field photocurrent imaging. Near-field photocurrent imaging has also been applied in the characterisation of quantum well laser devices, and powerfully combined with the complementary optical collection and topographic imaging modes. The photocurrent imaging mode probes the electronic device characteristics, whilst near-field collection imaging characterises the optical output of operating laser devices, the two independent imaging modes are correlated by the simultaneous surface topographies.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available