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Photoconductivity in Al x Ga 1—x N with Different Al Contents
Author(s) -
Meister D.,
Topf M.,
Dirnstorfer I.,
Meyer B.K.,
schwarz R.,
Heuken M.
Publication year - 1999
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/(sici)1521-3951(199911)216:1<749::aid-pssb749>3.0.co;2-t
Subject(s) - photoconductivity , excitation , photocurrent , metalorganic vapour phase epitaxy , epitaxy , materials science , optoelectronics , band gap , condensed matter physics , analytical chemistry (journal) , chemistry , physics , nanotechnology , layer (electronics) , quantum mechanics , chromatography
We report on the photoconductivity (PC) of Al x Ga 1— x N on GaN epitaxial films grown by metal organic vapor phase epitaxy (MOVPE) with Al contents between x = 0% and 18%. The concentration of the free carriers and mobilities of majority carriers are derived from Hall effect measurements. Temperature dependent photoconductivity measurements between 4.2 and 500 K have been performed. The ratio between the photoconductivity for sub‐bandgap excitation and that for excitation in the excitonic region drops down with increasing temperature to a value around 10 5 due to a decreasing relevance of electronic traps. Time transients after sub‐bandgap and UV‐excitation exhibit a prolonged non‐exponential decay of photoconductivity. We find a power law delay for the time transient of the photocurrent I ph ( t ) ∼ t — m ( m = 0.27 to 0.33) which can be explained in the picture of bandtails.