Radiative lifetime of excitons in ZnO nanocrystals: The dead-layer effect

Fonoberov, Vladimir A.; Balandin, Alexander A.

doi:10.1103/physrevb.70.195410

Cited by 113 publications

(28 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As the size of the nanostructure is reduced, the coherence volume of the exciton is also reduced leading to a decreasing oscillator strength and an increasing radiative lifetime. [91][92][93] The fact that the observed recombination time τ rec = τ 2 scales with E 3/2 loc as expected for the radiative lifetime τ indicates that τ rec is mostly determined by the radiative processes as was also pointed out by Heitz et al 86 The same relation between time constants and localization energies is valid for the short lifetime τ 1 and therefore also for the recapture process of excitons to deep traps (τ cap ). This can be explained within the same model considering that the probability for an exciton to be detached from the shallow donor and to be recaptured to deeper traps is proportional to the overlap between the localized exciton wave function and the trap region and, therefore, to the localization volume a 3 BE ∝ E −3/2 loc .…”

Section: G Recombination Dynamicsmentioning

confidence: 76%

Bound excitons in ZnO: Structural defect complexes versus shallow impurity centers

et al. 2011

View full text Add to dashboard Cite

ZnO single crystals, epilayers, and nanostructures often exhibit a variety of narrow emission lines in the spectral range between 3.33 and 3.35 eV which are commonly attributed to deeply bound excitons (Y lines). In this work, we present a comprehensive study of the properties of the deeply bound excitons with particular focus on the Y 0 transition at 3.333 eV. The electronic and optical properties of these centers are compared to those of the shallow impurity related exciton binding centers (I lines). In contrast to the shallow donors in ZnO, the deeply bound exciton complexes exhibit a large discrepancy between the thermal activation energy and localization energy of the excitons and cannot be described by an effective mass approach. The different properties between the shallow and deeply bound excitons are also reflected by an exceptionally small coupling of the deep centers to the lattice phonons and a small splitting between their two electron satellite transitions. Based on a multitude of different experimental results including magnetophotoluminescence, magnetoabsorption, excitation spectroscopy (PLE), time resolved photoluminescence (TRPL), and uniaxial pressure measurements, a qualitative defect model is developed which explains all Y lines as radiative recombinations of excitons bound to extended structural defect complexes. These defect complexes introduce additional donor states in ZnO. Furthermore, the spatially localized character of the defect centers is visualized in contrast to the homogeneous distribution of shallow impurity centers by monochromatic cathodoluminescence imaging. A possible relation between the defect bound excitons and the green luminescence band in ZnO is discussed. The optical properties of the defect transitions are compared to similar luminescence lines related to defect and dislocation bound excitons in other II-VI and III-V semiconductors.

show abstract

Section: G Recombination Dynamicsmentioning

confidence: 76%

Bound excitons in ZnO: Structural defect complexes versus shallow impurity centers

et al. 2011

View full text Add to dashboard Cite

show abstract

“…The peak at about 600 cm −1 is the characteristic absorption peak of Zn-O bond, which is the stretching mode of ZnO [12]. The other peaks at around 1083, 1468, 2852, and 2920 cm −1 are due to C-H bending and stretching [12,13], and the broad absorption peak at 3438.26 cm −1 can be attributed to the characteristic absorption of hydroxyls groups [13]. Comparing FTIR spectra of the samples synthesized using acetone (0.5 M) and Ethanol (2 M) in our last works [14], indicated that Zn-O bond has approximately the same concentration in both sample ( Figure 1).…”

Section: Resultsmentioning

confidence: 96%

Strong blue emission from ZnO nanocrystals synthesized in acetone-based solvent

Efafi

Ara

Mousavi

2016

Journal of Luminescence

View full text Add to dashboard Cite

“…While the average diameter of the In-doped nanoparticles is ca. 10 nm, about 5–6 times of the exciton Bohr radius of ZnO (1.8 nm), suggesting a likely presence of moderate quantum confinement effect (QCE) [19]. Theoretical calculations predict a blueshift of ~45 meV for ZnO nanoparticles with diameters of ca.…”

Section: Resultsmentioning

confidence: 99%

One-Step Synthesis of Monodisperse In-Doped ZnO Nanocrystals

Wang

Yang

et al. 2010

Nanoscale Res Lett

View full text Add to dashboard Cite

A method for the synthesis of high quality indium-doped zinc oxide (In-doped ZnO) nanocrystals was developed using a one-step ester elimination reaction based on alcoholysis of metal carboxylate salts. The resulting nearly monodisperse nanocrystals are well-crystallized with typically crystal structure identical to that of wurtzite type of ZnO. Structural, optical, and elemental analyses on the products indicate the incorporation of indium into the host ZnO lattices. The individual nanocrystals with cubic structures were observed in the 5% In–ZnO reaction, due to the relatively high reactivity of indium precursors. Our study would provide further insights for the growth of doped oxide nanocrystals, and deepen the understanding of doping process in colloidal nanocrystal syntheses.

show abstract

Radiative lifetime of excitons in ZnO nanocrystals: The dead-layer effect

Cited by 113 publications

References 24 publications

Bound excitons in ZnO: Structural defect complexes versus shallow impurity centers

Bound excitons in ZnO: Structural defect complexes versus shallow impurity centers

Strong blue emission from ZnO nanocrystals synthesized in acetone-based solvent

One-Step Synthesis of Monodisperse In-Doped ZnO Nanocrystals

Contact Info

Product

Resources

About