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Time‐ and bias‐dependent effects in ZnCd(Mg)Se blue and red quantum well light emitting diodes studied by cathodoluminescence
Author(s) -
Nikiforov A. Yu.,
Cargill III G. S.,
Guo S. P.,
Tamargo M. C.
Publication year - 2004
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/pssb.200304214
Subject(s) - cathodoluminescence , light emitting diode , luminescence , diode , blueshift , trapping , spectroscopy , biasing , optoelectronics , chemistry , electron , blue light , optics , materials science , analytical chemistry (journal) , physics , photoluminescence , voltage , ecology , chromatography , quantum mechanics , biology
Abstract Luminescence variations in MBE‐grown blue and red ZnCd(Mg)Se/InP QW LEDs have been studied by time‐resolved and bias‐dependent cathodoluminescence (CL) spectroscopy. CL from the red LED reversibly increased under forward bias and decreased under negative bias during several complete biasing cycles. CL from blue LEDs was bias dependent only during the first few cycles. The irreversible effects were QW CL intensity decreases after electron bombardment for the red LED and QW CL intensity enhancements seen as bright regions in CL images and dark regions in SE micrographs for blue LEDs. For the red LED, the bombarded regions were dark in CL images and had a dark dot and halo contrast in SE micrographs. The enhancements of CL intensity in the blue LEDs may result from buildup of internal fields due to persistent charge trapping in preexisting or electron bombardment created defects. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)