Epitaxial self-alignment: A new route to hybrid active plasmonic nanostructures

Abstract

ARTICLE INFO ABSTRACT Keywords: III-V semiconductors Quantum dot Lateral ordering Metal nanostructures Plasmonics Enhanced emission Enhanced absorptionConcepts of lateral ordering of epitaxial semiconductor quantum dots (QDs) are for the first time transferred to hybrid nanostructures for active plasmonics. We review our recent research on the selfalignment of epitaxial nanocrystals of In and Ag on ordered one-dimensional In(Ga)As QD arrays and isolated QDs by molecular beam epitaxy. By changing the growth conditions the size and density of the metal nanocrystals are easily controlled and the surface plasmon resonance wavelength is tuned over a wide range in order to match the emission wavelength of the QDs. Photoluminescence measurements reveal large enhancement of the emitted light intensity due to plasmon enhanced emission and absorption down to the single QD level.

Self-organized colloidal quantum dots and metal nanoparticles for plasmon-enhanced intermediate-band solar cells

“…An effect known as near-field enhancement which has been proposed for application in various types of thin-film solar cells [18,37,43,48], and also to epitaxially grown QD structures [8,20,21]. In this work, we're interested Figure 8.…”

“…In particular, several contributions showed enhanced photoluminescence [8,20,21,23, 24], due to plasmon-enhanced absorption at or above the QDs ground-state, when the exciting light matches the plasmonic resonance of appropriately designed MNPs located in a near-field vicinity of the dots. The interaction with the MNPs usually results, however, in a decrease of the luminescence lifetimes of the QDs [24].…”

“…As represented in figure 1, when QDs are embedded in a semiconductor with a higher bandgap, their confined ground-state level can allow the promotion of electrons from the valence to the conduction band of the host semiconductor through the absorption of two consecutive photons with energies below the host bandgap (£ev)-Therefore, QD-IBSCs are able to generate photocurrent from a higher portion of the solar spectrum relative to conventional single-gap cells, without voltage reduction [2,29,30]. QD-IBSCs have usually been fabricated with QDs epitaxially grown on III-V materials [8,10]. However, the use of colloidal QDs can be more advantageous, since they can be made of a broad range of materials, fabricated with the appropriate nanoscopic dimensions [9,11], and assembled together with MNPs, as described in section 2, which can potentially enhance the light absorption in the dots by more than one order of magnitude at their plasmon resonance [12,19].…”

“…During the last decade, research on semiconductor nanoparticles, also known as quantum dots (QDs), has been growing enormously, mostly stimulated by their potential for opto-electronic applications such as solar cells [1^1], photodetectors [5][6][7], semiconductor lasers [8], light-emitting devices, etc. QDs are attractive candidates for the building blocks of nanostructured functional materials, since their nanometric dimensions allow the size-tuning of their electronic band structure due to quantum-confinement effects.…”

“…Each MNP acts as an effective dipolar antenna at its localized plasmon resonance, bringing the incident energy from its surroundings and focusing it in its intense near-field where the QDs are located (sketched in figure 1) [7,8,[19][20][21].…”