Electronic states and curved surface effect of silicon quantum dots

Abstract

Articles you may be interested inEffect of band alignment on photoluminescence and carrier escape from InP surface quantum dots grown by metalorganic chemical vapor deposition on Si A mirage study of CdSe colloidal quantum dot films, Urbach tail, and surface states J. Chem. Phys. 137, 154704 (2012); 10.1063/1.4758318 The role of surface defects in multi-exciton generation of lead selenide and silicon semiconductor quantum dots J. Chem. Phys. 136, 064701 (2012); 10.1063/1.3682559 Effect of oxidation on the electronic structure of a Si 29 quantum dot: Calculations of redshifts in energy gap FIG. 2. Si ¼ O bond structures on curved surface (a) and on facet of Si QDs (b), and their density of states. 171601-2Huang et al.

Luminescent silicon nanocrystals produced by near-infrared nanosecond pulsed laser ablation in water

“…We observe that the origin of this PL is actually debated between two models: quantum confinement (QC) of excitons in the Si-NC or localized states at the Si-SiO 2 interface [17]. In particular, it has been evidenced that in small Si-NCs (size ∼3 nm) surface oxidation produces localized states at Si O Si bridge or Si O double bonds which favor the enhancement of the red emission [21,22]. Also the doping is expected to influence the PL properties; a recent work has indeed pointed out that n-and p-type codoping introduces donor and acceptor states that lower the PL energy transition [23].…”

Color-kinematic duality in ABJM theory without amplitude relations

“…In particular, the color-kinematic duality has been found in three-dimensional Chern-Simons-matter theories: the N = 8 Bagger-Lambert-Gustavsson (BLG) theory and the N = 6 Aharony-Bergman-Jafferis-Maldacena (ABJM) theory [16,17]. BLG theory turns out to be a special case of ABJM theory.…”

Lasing with Pumping Levels of Si Nanocrystals on Silicon Wafer

“…These phenomena may be related to the electronic localized states at 2 eV from Si–O–Si bridge bonds formed in dilute oxygen and the electronic localized states at 1.78 eV from Si=O bonds formed in concentrated oxygen [19]. After increasing annealing time to 20 min, the sharper peak near 600 nm in the PL spectrum is observed on the Si-NC structures prepared in dilute oxygen in which Si–O–Si bonds are easy to generate on the Si QDs, but they gradually disappear after annealing for 30 min, as shown in Fig.…”

“…It has been established that the spectrum of the photoluminescence (PL) emission from Si-NCs shifts to the blue due to the quantum confinement (QC) effect related to the rising electronic states which have shorter lifetime (in nanosecond (ns) scale) [17, 18] to be suitable for pumping levels, due to the Heisenberg principle related to ⊿ t  ~  h /⊿ E [19] in the QC effect. The results of experiment and calculation indicate the quantization-related open of the bandgap and the enhancement of the radiative recombination rate, as momentum conservation is gradually relaxed with decrease of nanocluster size.…”

“…On the other hand, the impurities of oxygen and nitrogen or the interface and defects lead to the forming of the electronic localization states into the bandgap due to broken symmetry of system, whose energy position refers to Si–O and Si–N bonds on curved surface (CS) related to smaller nanoclusters called CS effect [19, 20]. Here, the electronic localization states have a longer lifetime (in microsecond (μs) scale) [21, 22] to be suitable for producing inversion of population in the levels.…”