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Photocurrent near‐field microscopy of Schottky barriers
Author(s) -
Coluzza C.,
Di Claudio G.,
Davy S.,
Spajer M.,
Courjon D.,
Cricenti A.,
Generosi R.,
Faini G.,
Almeida J.,
Conforto E.,
Margaritondo G.
Publication year - 1999
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1046/j.1365-2818.1999.00504.x
Subject(s) - photocurrent , overlayer , materials science , schottky barrier , schottky diode , near field scanning optical microscope , photoemission electron microscopy , microscopy , photon energy , optoelectronics , optics , optical microscope , condensed matter physics , electron microscope , diode , photon , scanning electron microscope , physics , composite material
We used a combination of internal photoemission and of near‐field optical microscopy (SNOM) to study the lateral variations in solid interface properties such as energy barriers and electron–hole recombination. In particular we investigated the fully formed Pt–GaP, Au–GaAs, Au–SiN x –GaAs and PtSi–Si Schottky barriers. Our approach enabled us to measure large lateral variations in the photocurrent with spatial resolution on the nanometric scale. Due to the ability of SNOM to supply parallel topographic information, we observed photocurrent variations from zone to zone that only correlated in a few cases with local variations in surface morphology. We assigned the uncorrelated fluctuations to local variations in the interface stoichiometry, the presence of interface states induced by the metallic overlayer and to defect states at the junction. Furthermore, by tuning the photon energy and applied bias we were able to measure the surface distribution of the diffusion length.