Electroluminescence microscopy and spectroscopy of silicon nanocrystals in thin SiO2 layers
2001 (English)In: Optical materials (Amsterdam), ISSN 0925-3467, Vol. 17, no 02-jan, 45-50 p.Article in journal (Refereed) Published
Stable continuously operable electroluminescent diodes have been fabricated by Sii-ion implantation and annealing of thin SiO2 layers on a silicon substrate. The external quantum efficiency of the device is reaching 3 x 10(-5) for the best diodes. Electroluminescence (EL) emission band is wide and centered at 800 nm. EL is due to radiative recombination of tunneling carriers in Si-nanocrystals(NC) with small contribution of oxide defects (peak at 650 nm). EL images reveal inhomogeneous emission structures on the micrometer scale. Mainly, a small number of bright spots with diffraction limited size (similar to 600 nm) with a homogeneous background are observed and their EL spectra measured using an imaging spectrometer with a liquid-nitrogen-cooled CCD camera. The bright EL spots originate from the efficiently excited emission of oxide defects and/or emission of a few (possibly single) Si-NC, most likely at places with locally increased current. The low efficiency is probably a consequence of current tunneling through optically inactive nanocrystals or defects in a very thin oxide layer.
Place, publisher, year, edition, pages
2001. Vol. 17, no 02-jan, 45-50 p.
nanocrystals, electroluminescence, photoluminescence, implantation, LED, quantum efficiency, luminescence, photoluminescence, diode
IdentifiersURN: urn:nbn:se:kth:diva-20776ISI: 000169788700011OAI: oai:DiVA.org:kth-20776DiVA: diva2:339473
QC 201005252010-08-102010-08-10Bibliographically approved