scholarly journals Emergence of Distinct Electronic States in Epitaxially-Fused PbSe Quantum Dot Superlattices

2021 ◽  
Author(s):  
Mahmut Sami Kavrik ◽  
Jordan Hachtel ◽  
Wonhee Ko ◽  
Caroline Qian ◽  
Alex Abelson ◽  
...  
Keyword(s):  
Band Gap ◽  
High Efficiency ◽  
Electronic States ◽  
Scanning Tunneling Spectroscopy ◽  
Band Gap Energy ◽  
Scanning Tunneling ◽  
Material System ◽  
High Efficiency Solar Cells ◽  
Electron Energy Loss ◽  
Band Gap Modulation

Abstract Quantum coupling in arrayed nanostructures may induce novel mesoscale properties such as electronic minibands that may lead to applications including high efficiency solar cells. Colloidal PbSe quantum dots (QDs) can self-assemble into epitaxially-fused superlattices (epi-SLs), making them a promising material system to study collective phenomena. In the present study, the presence of distinct local electronic states induced by crystalline necks connecting individual PbSe QDs is documented by several techniques that leads to modulation of the band gap energy across the epi-SL. The energy band gap measured by multi-probe scanning tunneling spectroscopy (STS) shows variation from 0.7 eV at the center of the QDs to 1.1 eV at their necks. Complementary monochromated electron energy-loss spectroscopy (EELS) measurements reveal the presence of distinct electronic states from necks in the epi-SL, confirming the STS measurements and demonstrating band gap modulation in spectral mapping. It is hypothesized that these new electronic states are induced by quantum confinement of carriers in the necks between the QDs, redefining the energy landscape of the PbSe QD epi-SL.

Metallic Tin-Filling Effects on Carbon Nanotubes Revealed by Atomically Resolved Spectro-Microscopies

2008 ◽  
Vol 3 ◽  
pp. 1-6 ◽  
Author(s):  
E. Maccallini ◽  
G. Kalantzopoulos ◽  
T. Tsoufis ◽  
R.G. Agostino ◽  
G. Chiarello ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Band Gap ◽  
Local Density ◽  
Electronic States ◽  
Scanning Tunneling Spectroscopy ◽  
Scanning Tunneling ◽  
Local Density Of States ◽  
Multi Wall Carbon Nanotubes ◽  
Spatially Resolved ◽  
Topology Changes

The identification of features in the Local Density of States (LDOS) of carbon nanotubes (CNTs) obtained by Scanning Tunneling Spectroscopy (STS) is of great importance in order to understand their properties. In this work, Single- and Multi-Wall Carbon Nanotubes are compared with Multi-Wall CNTs filled with tin nanowires (Sn@CNTs) in order to investigate the effect on morphological and electronic properties of the CNTs metallic filling. The LDOS of CNTs, together with topology changes, is investigated by using spatially resolved STM/STS at room temperature and in air and compared to the LDOS of highly oriented pyrolitic graphite (HOPG). The LDOS of CNTs is dominated from different electronic states filling the C 2pσ-2pσ* band gap. The appearance of those states is linked to the diameter and the defects of the CNTs. In fact, Snnanowires encapsulation induces changes in the structure of the CNTs and the appearance of electronic states in the LDOS inside the band gap. A more extensive description of the samples is obtained depicting the morphological features and the vibrational structure on wider areas using Scanning Electron Microscopy (SEM) and Raman spectroscopy, respectively.

scholarly journals Band gap of theGe(111)c(2×8)surface by scanning tunneling spectroscopy

2006 ◽  
Vol 73 (3) ◽  
Author(s):  
R. M. Feenstra ◽  
J. Y. Lee ◽  
M. H. Kang ◽  
G. Meyer ◽  
K. H. Rieder
Keyword(s):  
Band Gap ◽  
Scanning Tunneling Spectroscopy ◽  
Tunneling Spectroscopy ◽  
Scanning Tunneling

scholarly journals Tunable Narrow Band Gap Absorbers For Ultra High Efficiency Solar Cells

2012 ◽  
Author(s):  
Salah M. Bedair ◽  
◽  
John R. Hauser ◽  
Nadia Elmasry ◽  
Peter C. Colter ◽  
...  
Keyword(s):  
Solar Cells ◽  
Band Gap ◽  
High Efficiency ◽  
Narrow Band ◽  
High Efficiency Solar Cells

scholarly journals Electronic states of InAs/GaAs quantum dots by scanning tunneling spectroscopy

2010 ◽  
Vol 97 (12) ◽  
pp. 123110 ◽  
Author(s):  
S. Gaan ◽  
Guowei He ◽  
R. M. Feenstra ◽  
J. Walker ◽  
E. Towe
Keyword(s):  
Quantum Dots ◽  
Electronic States ◽  
Scanning Tunneling Spectroscopy ◽  
Tunneling Spectroscopy ◽  
Scanning Tunneling

scholarly journals Переход металл-полупроводник в нанопленках иттербия, индуцированный адсорбированными молекулами кислорода

2021 ◽  
Vol 91 (7) ◽  
pp. 1189
Author(s):  
М.В. Кузьмин ◽  
М.А. Митцев
Keyword(s):  
Electronic Structure ◽  
Crystal Lattice ◽  
Band Gap ◽  
Scanning Tunneling Spectroscopy ◽  
Tunneling Spectroscopy ◽  
Quantum States ◽  
Scanning Tunneling ◽  
Bonding Type ◽  
First Time

The influence of nondissociative adsorption of oxygen molecules on the electronic structure of ytterbium films with the thickness of 16 monolayers (6.08 nm) has been studied for the first time by using scanning tunneling spectroscopy. It is established that the adsorption of O2 molecules induces the metal-semiconductor transition in ytterbium. As a result of this transition, the quantum states have disappeared in the films, which evidences for a change of bonding type in the ytterbium crystal lattice, as well as the band gap of ~0.72 eV has opened.

scholarly journals Yu-Shiba-Rusinov bands in ferromagnetic superconducting diamond

2020 ◽  
Vol 6 (20) ◽  
pp. eaaz2536
Author(s):  
Gufei Zhang ◽  
Tomas Samuely ◽  
Naoya Iwahara ◽  
Jozef Kačmarčík ◽  
Changan Wang ◽  
...  
Keyword(s):  
Lattice Structure ◽  
Three Dimensional ◽  
Superconducting Devices ◽  
Electronic States ◽  
Scanning Tunneling Spectroscopy ◽  
Scanning Tunneling ◽  
Boron Doped Diamond ◽  
Spin Lattice ◽  
Boron Doped ◽  
Potential Applications

The combination of different exotic properties in materials paves the way for the emergence of their new potential applications. An example is the recently found coexistence of the mutually antagonistic ferromagnetism and superconductivity in hydrogenated boron-doped diamond, which promises to be an attractive system with which to explore unconventional physics. Here, we show the emergence of Yu-Shiba-Rusinov (YSR) bands with a spatial extent of tens of nanometers in ferromagnetic superconducting diamond using scanning tunneling spectroscopy. We demonstrate theoretically how a two-dimensional (2D) spin lattice at the surface of a three-dimensional (3D) superconductor gives rise to the YSR bands and how their density-of-states profile correlates with the spin lattice structure. The established strategy to realize new forms of the coexistence of ferromagnetism and superconductivity opens a way to engineer the unusual electronic states and also to design better-performing superconducting devices.

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