Purcell effect for CdSe∕ZnSe quantum dots placed into hybrid micropillars

Abstract

This letter reports the observation of the Purcell effect for CdSe∕ZnSe quantum dots located in a hybrid micropillar. The sample consist of a λ∕2-ZnSe cavity sandwiched between two SiO2∕TiO2 Bragg reflectors. Time-resolved photoluminescence (PL) measurements on a series of single-quantum dots were used to probe the Purcell effect in a 1.1μm diameter pillar. A three-fold enhancement of quantum-dot spontaneous emission rate is observed for quantum dots in resonance with excited degenerated modes of the pillar. The variation of the PL decay shortening from dot to dot is interpreted calculating the theoretical maximal Purcell factor for the different modes resonant with the dots.

Properties and prospects of blue–green emitting II–VI‐based monolithic microcavities

“…[21]. In relation to the recombination time of QDs in a ZnSe matrix (460 ps) an SE enhancement value F eff = 3.8 can thus be stated for the pillar with 0.7 µm diameter ( f τ = 120 ps, see above) which is comparable to the value reported in [44] for CdSe/ZnSe QDs embedded into hybrid micropillars. To calculate the effective enhancement factor it has to be taken into account that the coupling of an emitter to a cavity mode depends both on the spectral matching of the emitter emission line e ω to the cavity mode frequency c ω , and on the spatial overlap of the emitter with the mode.…”

“…By utilization of the zinc selenide wide-bandgap system, MCs for the blue to green spectral region can be realized. While such structures made of dielectric material like SiO 2 and TiO 2 or SiN can be produced routinely [40][41][42][43][44], there are only few reports about monolithic ZnSe-based MCs. Because epitaxial DBRs are dopable in principle [45,46], they are essential for effective current injection and cost-effective device processing e.g.…”

“…10 experimental spontaneous emission enhancement factors are shown versus the corresponding maximum calculated ones. The Purcell factor F relates the SE rate 1 τ / of an emitter in Figure 10 Purcell effect in hybrid pillar microcavities: experimental versus calculated enhancement factor for CdSe QDs resonant with lowest modes (HE ij and EH ij ) of the micropillar cavity with a diameter of 1.1 µm [44].…”

Purcell effect on CdSe/ZnSe quantum dots in pillar microcavities

“…In the following, the experimental enhancement factors τ free /τ cavity are compared to the calculated one, taking into account the cumulative contributions when several modes spectrally overlap. The calculations are performed following [6] and are detailed in [7]. Optical characterizations demonstrating the Purcell effect consist in measuring the PL decay time (4 K) for a few QD lines in resonance with different modes of a 1.1 µm micropillar.…”

CdSe/ZnSe quantum dots coupled to modes of monolithic II‐VI pillar microcavities: tunability and Purcell effect

“…With respect to the realization of an efficient single-photon source the coupling of QDs to discrete modes of a high-Q microcavity (MC) [2,3] is highly desirable and has been shown in the case of CdSe QDs only recently for hybrid MCs [4]. We report on the emission properties of CdSe/ZnSe QDs embedded in all-epitaxial ZnSebased pillar MCs studied in temperature variable and time resolved photoluminescence (PL) spectroscopy.…”