Energy Transfer in Multi-Stacked InAs Quantum Dots

Abstract

We fabricated a modulated stacked quantum dot (QD) structure to investigate energy transfer among QDs using a strain compensation technique that allowed us to fabricate a vertically aligned, highly stacked structure without any degradation in crystal quality. Enhanced photoluminescence (PL) intensity for the ground state of large QDs was clearly observed in a sample where the ground state of small QDs was resonant to the first excited state of large QDs, indicating energy transfer from small QDs to large QDs. Long-range energy transfer reached approximately 200 nm and can be considered from the measurement of N dependence of PL intensity.

Dressed photon technology

“…The output optical spot diameter was <10 nm, and the time required for energy transfer to the central largest QD was about 1 ns, which is governed by the time constant for dressed photon exchange. For room-temperature operation of this device, multi-layered InAs QDs were grown by molecular beam epitaxy, as in the case of Figure 1 [23] . A layer of large QDs was sandwiched by 30 layers of small QDs.…”

Analysis of optical near-field energy transfer by stochastic model unifying architectural dependencies

“…17 What is important is to regulate the size and the position of nanostructures so that optical near-field interactions are induced between them in order to obtain designated functions. 19 This gives rise to the importance of modeling of nanophotonic devices and systems composed of multiple nanostructures arranged in varying configurations in characterizing and designing designated functions, such as efficient energy concentration, 20 wavelength conversion, 21 sensing, 22 color rendering for lighting and displays, 16 and many others. Technologies such as droplet epitaxy 23 and light-assisted quantum-dot size formation 24 have been developed, enabling geometry-regulated fabrication of nanostructured matter.…”

“…20 Akahane et al. have developed an original molecular beam epitaxy (MBE) technology for realizing multilayer QD structures, where the size of the QDs in each layer and the inter-layer distances are precisely and individually controlled.…”

“…26 Moreover, they have developed multi-layer QD devices in which one layer contains larger-sized QDs that are sandwiched by multiple layers of smaller-sized QDs. 20 More precisely, N and N+1 layers (where N is an integer) of smaller-sized QDs were located respectively below and above the larger-QD layer, as schematically shown in Fig. 1(a).…”

“…The presumable physical reasons behind this were mentioned in Ref. 20, but no precise modeling or quantitative discussions were given; this is an immediate typical case where a theoretical approach unifying device architectures, inherent disorder, and optical near-field interactions is necessary. This paper also expands on the experimental results reported in Ref.…”