Enhancement of photoluminescence from near-surface quantum dots by suppression of surface state density

Electrochemical stabilization of crystalline silicon with aromatic self‐assembled monolayers in aqueous electrolytes

“…Previously, we demonstrated the electrochemical passivation of GaAs surfaces with monolayers of alkylthiols under physiological conditions, i.e., at neutral pH in aqueous electrolytes [3,4]. Suppression of the surface state density due to the covalent As-S coupling could also be observed by photoluminescence signals from near-surface InAs quantum dots [5]. More recently, we engineered the surface of bulk GaAs and surface-near two-dimensional electron gases (2DEGs) in GaAs/AlGaAs heterostructures with various 4′-4-mercaptobiphenyl monolayers and found…”

Fabrication, spectroscopy, and dynamics of highly luminescent core–shell InP@ZnSe quantum dots

“…Many groups have spent considerable time and effort on the solution phase synthesis of InP nanoparticles using diverse methods such as a dehalosilylation reaction method or a hot injection technique [17][18][19][20]. However, InP nanocrystals synthesized in organic solutions show quite low band-edge photoluminescence due to surface traps, dangling bonds, stacking faults, and a high activation barrier for carrier detrapping [21][22][23]. Because of large surface-to-volume ratios of small nanoparticles, photoexcited electrons in their conduction bands are extensively trapped into surface states.…”

“…Quantum dots exhibit narrow photoluminescence profiles that can be tuned by treating their defect sites with the elimination of both anionic and cationic dangling bonds at their surfaces. The surfaces of nanoparticles can be tailored physically via thermal treatment or chemically via organic or inorganic capping to enhance photoluminescence profoundly [21][22][23][24][25][26][27]. Thus, to improve the photoluminescence of InP quantum dots, surface phosphorous atoms lying at the origins of trap sites were removed by being etched with HF or nanocrystals were passivated with shell materials that have wider band gaps [17,[24][25][26][27].…”

Monolithically integrated single quantum dots coupled to bowtie nanoantennas

“…Lithographically defined plasmonic dimer antennas, such as bowties [14], are most prominent amongst the zoo of metallic nanoparticles since they simultaneously provide strong light confinement in subwavelength sized hot-spots, large-range spectral tunability and facilitate electrical access [19] and full control of the emission polarisation [20]. As a result, the quantum dot coupled nanoantennas offer new perspectives to probe light-matter-couplings and cavity quantum electrodynamics (cQED) effects beyond the point-dipole approximation [21].In this Letter, we coupled individual quantum dots to plasmonic nanoantennas to form a novel cQED-system schematically illustrated in figure 1 (a), which consists of near-surface (d ∼ 10 nm) InAs/AlGaAs quantum dots [22] and lithographically defined triangular bowtie nanoantennas [14] arranged in a square array (left scanning electron microscopy image in figure 1 (b)) with a lattice constant a = 1.5 µm. A typical nanoantenna with triangle size s = 87±3 nm and feed-gap size g = 26±3 nm as shown in the right scanning electron microscopy image in figure 1 (b).…”

“…In this Letter, we coupled individual quantum dots to plasmonic nanoantennas to form a novel cQED-system schematically illustrated in figure 1 (a), which consists of near-surface (d ∼ 10 nm) InAs/AlGaAs quantum dots [22] and lithographically defined triangular bowtie nanoantennas [14] arranged in a square array (left scanning electron microscopy image in figure 1 (b)) with a lattice constant a = 1.5 µm. A typical nanoantenna with triangle size s = 87±3 nm and feed-gap size g = 26±3 nm as shown in the right scanning electron microscopy image in figure 1 (b).…”