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Near‐field scanning optical microscopy and near‐field induced photocurrent investigations of buried heterostructure multiquantum well lasers
Author(s) -
ACKLAND M. P.,
DUNSTAN P. R.,
REES P.
Publication year - 2005
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 - 10.1111/j.1365-2818.2005.01529.x
Subject(s) - photocurrent , heterojunction , materials science , laser , near field scanning optical microscope , optoelectronics , optical microscope , optics , microscopy , electroluminescence , scanning electron microscope , physics , nanotechnology , composite material , layer (electronics)
Summary Buried heterostructure multiquantum well laser devices are investigated utilizing a near‐field scanning optical microscope to characterize and correlate the surface topography, optical output and electronic properties of the device. Near‐field photocurrent imaging has been used to accurately measure the unbiased buried heterostructure multiquantum well device in cross‐section, successfully revealing the distribution of pn ‐junctions and their associated fields. Moreover, this has been accurately correlated with the physical structure of the device determined by simultaneous shear‐force imaging of the surface. Topographic structure is manifested as a result of strain relaxation (∼10 −10 m) of the cleaved cross‐section. These imaging modes are similarly correlated with the optical output of the operational device mapped with 50 nm lateral resolution. The collection‐mode measurements detected electroluminescence external to the active region, highlighting the existence of carrier recombination away from the multiquantum well device region. The combination and correlation of different near‐field scanning optical microscope imaging modes proved powerful in the analysis of the buried heterostructure multiquantum well device, and was shown to assist in the identification of current leakage pathways within the structure.