Unraveling electronic band structure of narrow-bandgap p–n nanojunctions in heterostructured nanowires

Zamani, Reza; Hage, Fredrik S.; Eljarrat, Alberto; Namazi, Luna; Ramasse, Quentin M.; Dick, Kimberly A.

doi:10.1039/d1cp03275e

Cited by 7 publications

(3 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…With the electronic structure isolated from instrumental and environmental artifacts, we can apply band-edge fitting to the onset of the EELS intensity in the PbSe QDs. Here, we use the fitting model for direct bandgaps suggested by Zamani et al to fit onsets in the EEL intensity 34 . EELS probes the electronic structure by measuring the energy loss associated with transitions from the valence band to the conduction band, making it analogous to the joint density of states (JDOS) 33 .…”

Section: Resultsmentioning

confidence: 99%

Emergence of distinct electronic states in epitaxially-fused PbSe quantum dot superlattices

Kavrik

Hachtel

et al. 2022

Nat Commun

View full text Add to dashboard Cite

Quantum coupling in arrayed nanostructures can produce novel mesoscale properties such as electronic minibands to improve the performance of optoelectronic devices, including ultra-efficient solar cells and infrared photodetectors. Colloidal PbSe quantum dots (QDs) that self-assemble into epitaxially-fused superlattices (epi-SLs) are predicted to exhibit such collective phenomena. Here, we show the emergence of distinct local electronic states induced by crystalline necks that connect individual PbSe QDs and modulate the bandgap energy across the epi-SL. Multi-probe scanning tunneling spectroscopy shows bandgap modulation from 0.7 eV in the QDs to 1.1 eV at their necks. Complementary monochromated electron energy-loss spectroscopy demonstrates bandgap modulation in spectral mapping, confirming the presence of these distinct energy states from necking. The results show the modification of the electronic structure of a precision-made nanoscale superlattice, which may be leveraged in new optoelectronic applications.

show abstract

Section: Resultsmentioning

confidence: 99%

Emergence of distinct electronic states in epitaxially-fused PbSe quantum dot superlattices

Kavrik

Hachtel

et al. 2022

Nat Commun

View full text Add to dashboard Cite

show abstract

“…Based on the contribution and distribution of photogenerated carriers over Pd-(111)/(100)CeO 2– x , the first-step reaction in Pd-(111)CeO 2– x (or (111)CeO 2– x ) is identified to be the activation of O 2 by photogenerated electrons, while the first-step reaction in Pd-(100)CeO 2– x (or (100)CeO 2– x ) is identified to be the activation of NO by photogenerated holes, as shown in Figure b. To specify, the density functional theory (DFT) calculations were implemented using Quantum-ESPRESSO by the PWscf code. − The projector augmented wave (PAW) pseudopotentials were used to describe the interactions between valence electrons and ionic cores . The Perdew–Burke–Ernzerhof (PBE) form of the generalized gradient approximation (GGA) was employed to describe electronic exchange and correlation .…”

Section: Resultsmentioning

confidence: 99%

“X-Scheme” Charge Separation Induced by Asymmetrical Localized Electronic Band Structures at the Ceria Oxide Facet Junction

Rao

Huang

et al. 2023

ACS Catal.

View full text Add to dashboard Cite

Photogenerated charge transfer can be tuned by crystal face controlling and heterostructure engineering. However, it is exceptionally challenging to understand the separation and transfer process of charge carriers, especially on the facet junction. Here, we show a separation pathway of the charge carriers in (111)/(100)CeO 2−x nanomaterials as the "X-Scheme junction" using selected region electron energy-loss spectroscopies. The driving force for the "X-Scheme junction" can be attributed to the localized electronic band structures' asymmetry of the ceria, which gathers the photogenerated electrons on the surface of the (111) plane and accumulates the photogenerated holes on the (100) face. Surface oxygen vacancies channel the photogenerated electrons and holes further to the Ce 3+ of the (111) plane and the Ce 4+ of the (100) plane, respectively, resulting in an enhanced photo-oxidative nitric oxide removal efficiency under visible-light irradiation. Furthermore, the system is found to integrate metal nanoparticles to form Pd− CeO 2−x , including Pd-(111)CeO 2−x and Pd-(100)CeO 2−x , which significantly restricts nitric dioxide production as a byproduct. This work provides a unique approach to understanding single-crystal photocatalysts based on the facet junction.

show abstract

“…The electronic band structure is one of the most significant basic properties of a material and is in particular essential in electronic, photo-electronic, and photocatalytic applications [51]. The electronic band structure of semiconductors has a significant impact on the material's final electronic and optical properties, as well as the functionality of the devices that incorporate them [52]. The energy band structure for GaAs 0.5 N 0.5 alloy for two different values of pressure p = 0 kbar (solid lines) and p = 120 kbar (dashed lines) at L, Г and X high symmetry points is displayed in Fig.…”

Section: Rults and Discussionmentioning

confidence: 99%

Influence of pressure and composition on electronic properties, phonon frequencies, and sound velocity for the zinc-blende GaAs1-xNx alloy

Maaitah

Elkenany

2022

J Comput Electron

View full text Add to dashboard Cite

We investigated the electronic, phonon frequencies, and sound velocity of GaAs1-xNx ternary semiconductor alloys with the zinc-blende crystal structure over the entire nitrogen concentration range (with x from 0 to 1) using the empirical pseudo-potential model within the virtual crystal approximation including the compositional disorder effect. The pressure-dependent electronic, phonon frequencies and sound velocity of GaAs1-xNx ternary alloy have been studied. Our findings and the existing experimental data are found to be in good agreement. According to the dependence on pressure, a rising bandgap is predicted for GaAs1-xNx alloys at high-pressure values. According to the findings of this study, the GaAs1-xNx characteristics could have substantial optoelectronic applications in the infrared and mid-infrared spectral ranges.

show abstract

Unraveling electronic band structure of narrow-bandgap p–n nanojunctions in heterostructured nanowires

Abstract: The electronic band structure of complex nanostructured semiconductors has a considerable effect on the final electronic and optical properties of the material and, ultimately, on the functionality of the devices...

Cited by 7 publications

References 22 publications

Emergence of distinct electronic states in epitaxially-fused PbSe quantum dot superlattices

Emergence of distinct electronic states in epitaxially-fused PbSe quantum dot superlattices

“X-Scheme” Charge Separation Induced by Asymmetrical Localized Electronic Band Structures at the Ceria Oxide Facet Junction

Influence of pressure and composition on electronic properties, phonon frequencies, and sound velocity for the zinc-blende GaAs1-xNx alloy

Contact Info

Product

Resources

About