Femtosecond Spectroscopy of Carrier Relaxation Dynamics in Type II CdSe/CdTe Tetrapod Heteronanostructures

Peng, Panpan; Milliron, Delia J.; Hughes, Steven M.; Johnson, Justin C.; Alivisatos, A. Paul; Saykally, Richard J.

doi:10.1021/nl0680006

Cited by 35 publications

(57 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[10] The driving force for the formation of these unique morphologies is the minimization of the electrostatic interaction energy of the polar surface. [2] To date, different compositive tetrapod nanostructures [11][12][13][14][15][16][17][18] were reported, however, to obtain patterned or ordered growth of tetrapods remains a great challenge. Here, we show that surface polarity can induce novel asymmetric growth of ZnS dual-phase tetrapod tree-like heterostructures (a single compound with two crystal phases).…”

Section: Introductionmentioning

confidence: 99%

Growth, Cathodoluminescence and Field Emission of ZnS Tetrapod Tree‐like Heterostructures

Chen¹,

Zou²,

Liu³

et al. 2008

Adv Funct Materials

View full text Add to dashboard Cite

We report the growth mechanism, cathodoluminescence and field emission of dual phase ZnS tetrapod tree‐like heterostructures. This novel heterostructures consist of two phases: zinc blende for the trunk and hexagonal wurtzite for the branch. Direct evidence is presented for the polarity induced growth of tetrapod ZnS trees through high‐resolution electron microscopy study, demonstrating that Zn‐terminated ZnS (111)/(0001) polar surface is chemically active and S‐terminated (${\bar 1}$${\bar 1}$${\bar 1}$)/(000$\bar 1$) polar surface is inert in the growth of tetrapod ZnS trees. Two strong UV emissions centered at 3.68 and 3.83 eV have been observed at room temperature, which are attributed to the bandgap emissions from the zinc blende trunk and hexagonal wurtzite branch, indicating that such structures can be used as unique electromechanical and optoelectronic components in potential light sources, laser and light emitting display devices. In addition, the low turn‐on field (2.66 Vµm−1), high field‐enhancement factor (over 2600), large current density (over 30 mAcm−2 at a macroscopic field of 4.33 Vµm−1) and small fluctuation (∼1%) further indicate the availability of ZnS tetrapod tree‐like heterostructures for field emission panel display. This excellent field‐emission property is attributed to the specific crystallographic feature with high crystallinity and cone‐shape patterned branch with nanometer‐sized tips. Such a structure may optimize the FE properties and make a promising field emitter.

show abstract

Section: Introductionmentioning

confidence: 99%

Growth, Cathodoluminescence and Field Emission of ZnS Tetrapod Tree‐like Heterostructures

Chen¹,

Zou²,

Liu³

et al. 2008

Adv Funct Materials

View full text Add to dashboard Cite

show abstract

“…For allowed direct type of transitions: where α is the absorption coefficient, ( h ν) is the photon energy, and A is a constant. Figure 9(B) shows the variation of (α h ν) 2 vs ( h ν) for the CdSe nanocrystals, displaying an optical band gap of 2.09 eV, which is larger than the reported value of bulk CdSe ( E g =1.75 eV) 1 . This blue shift of band gap value can be attributed to the nanoscale size effect of the CdSe crystallines 35 …”

Section: Resultsmentioning

confidence: 81%

“…T he CdSe is an important engineering‐related II–VI group compound semiconductor with a direct energy band gap of 1.75 eV 1 . Nanoscale CdSe has attracted great attention in the past decade due to its unique properties supplying for potential luminescence and photoelectronic applications, such as biological fluorescent labels, 2,3 light‐emitting diodes, 4 lasers, 5 and solar cells 6 .…”

Section: Introductionmentioning

confidence: 99%

Nanosized CdSe Particles Synthesized by an Air Pressure Solution Process Using Ethylene‐Glycol‐Based Solvent

Wang

Jin

Liu

et al. 2010

Journal of the American Ceramic Society

View full text Add to dashboard Cite

Nanosized CdSe particles were synthesized at a temperature of 1151-1751C by a solution method with air pressure condition. Ethylene glycol (EG) was used as the main solvent and sodium selenite and cadmium nitrate-tetrahydrate as inorganic sources. The influence of refluxing temperature and time on growth morphology and crystallization was investigated by transmission electron microscope, high-resolution transmission electron microscope, and X-ray diffraction. The chemical reaction was deducted based on X-ray photoelectron spectra. The optical absorption property was measured by UV-vis. The CdSe nanoparticles synthesized through this EG solvent system was single wurtzite crystallization and had a nanoscale size below 15 nm diameter with a narrow size distribution. The reduction of Se 41 -Se 0 -Se 2À and the disproportionation of Se 0 occurred during the synthetic process and dominated the chemical reaction.

show abstract

“…In this, the core material is surrounded by a different shell material in order to reduce the influence of the possibly imperfect surface onto the core. Indeed, semiconductor core-shell NCs with a high photoluminescence quantum efficiency were reported 1,5,[20][21][22][23][24] .…”

Section: Introductionmentioning

confidence: 99%

Heavy strain conditions in colloidal core-shell quantum dots and their consequences on the vibrational properties fromab initiocalculations

Han

Bester

2015

Phys. Rev. B

View full text Add to dashboard Cite

We preform large-scale ab initio density functional theory calculations to study the lattice strain and the vibrational properties of colloidal semiconductor core-shell nanoclusters with up to one thousand atoms (radii up to 15.6Å). For all the group IV, III-V and II-VI semiconductors studied, we find that the atom positions of the shell atoms, seem unaffected by the core material. In particular, for group IV core-shell clusters the shell material remains unstrained, while the core adapts to the large lattice mismatch (compressive or tensile strain). For InAs-InP and CdSe-CdS, both the cores and the shells are compressively strained corresponding to pressures up to 20 GPa. We show that this compression, which contributes a large blue-shift of the vibrational frequencies, is counterbalanced, to some degree, by the undercoordination effect of the near-surface shell, which contributes a red-shift to the vibrational modes. These findings lead to a different interpretation of the frequency shifts of recent Raman experiments, while they confirm the speculated interface nature of the low-frequency shoulder of the high frequency Raman peak.

show abstract

Femtosecond Spectroscopy of Carrier Relaxation Dynamics in Type II CdSe/CdTe Tetrapod Heteronanostructures

Cited by 35 publications

References 0 publications

Growth, Cathodoluminescence and Field Emission of ZnS Tetrapod Tree‐like Heterostructures

Growth, Cathodoluminescence and Field Emission of ZnS Tetrapod Tree‐like Heterostructures

Nanosized CdSe Particles Synthesized by an Air Pressure Solution Process Using Ethylene‐Glycol‐Based Solvent

Heavy strain conditions in colloidal core-shell quantum dots and their consequences on the vibrational properties fromab initiocalculations

Contact Info

Product

Resources

About