Abstract
Enhanced electroluminescence (EL) has been achieved from the light-emitting devices containing Si quantum dots/SiO2 multilayers deposited on Si nanowire arrays because of the good antireflection characteristics of Si nanowire structures, which improves the light extraction efficiency. However, it is found that the EL is first enhanced with increasing the depth of the Si nanowires and then reduced to further increase the depth, though it exhibits the lowest reflectance (∼3%), which may be due to the increased surface defect states after long time etching, as revealed by electron spin resonance measurements. It is demonstrated that the posthydrogen plasma annealing treatments can passivate the surface defect states which, in turn, improve device performance. The best device shows the turn-on voltage as low as 3.5 V, and the EL intensity of devices on Si nanowire arrays is enhanced 16-fold, compared with that of flat one.
Highlights
The absorption and emission of light in bulk Si material is relatively poor due to its indirect bond gap structures
The reflectance of the flat Si substrate is higher than 35% in the whole measurement spectral range, and it is dramatically suppressed after forming Si nanowire (Si NW) structures
The light emitting devices containing Si quantum dots (Si QDs)/SiO2 multilayers fabricated on Si NW arrays exhibited the enhanced electroluminescence compared with that of flat one
Summary
The absorption and emission of light in bulk Si material is relatively poor due to its indirect bond gap structures. A modified nano-sphere lithography technique was used to get periodically nano-patterned Si structures. Both the photoluminescence and electroluminescence were significantly enhanced with increasing the depth of Si nanostructures, which can be attributed to the good light trapping effect since the reflectance was obviously suppressed in a wide spectral range despite of the relatively low aspect ratio. A good anti-reflection behavior is confirmed in a wide spectral range and the reflectance is gradually suppressed with increasing the etching depth. The prototype light emitting devices containing Si QDs/SiO2 multilayers are fabricated on Si NW arrays, and they show the enhanced electroluminescence compared with that of flat one. It is found that the electroluminescence is enhanced after hydrogen plasma annealing treatments
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
