scholarly journals Multiple hot-carrier collection in photo-excited graphene Moiré superlattices

2016 ◽  
Vol 2 (5) ◽  
pp. e1600002 ◽  
Author(s):  
Sanfeng Wu ◽  
Lei Wang ◽  
You Lai ◽  
Wen-Yu Shan ◽  
Grant Aivazian ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Single Photon ◽  
Power Conversion ◽  
Low Energy ◽  
Zero Bias ◽  
Hot Carrier ◽  
Emergent Phenomenon ◽  
Carrier Collection ◽  
Superlattice Structures ◽  
Standard Limit

In conventional light-harvesting devices, the absorption of a single photon only excites one electron, which sets the standard limit of power-conversion efficiency, such as the Shockley-Queisser limit. In principle, generating and harnessing multiple carriers per absorbed photon can improve efficiency and possibly overcome this limit. We report the observation of multiple hot-carrier collection in graphene/boron-nitride Moiré superlattice structures. A record-high zero-bias photoresponsivity of 0.3 A/W (equivalently, an external quantum efficiency exceeding 50%) is achieved using graphene’s photo-Nernst effect, which demonstrates a collection of at least five carriers per absorbed photon. We reveal that this effect arises from the enhanced Nernst coefficient through Lifshtiz transition at low-energy Van Hove singularities, which is an emergent phenomenon due to the formation of Moiré minibands. Our observation points to a new means for extremely efficient and flexible optoelectronics based on van der Waals heterostructures.

Preliminary Results of Low Energy Sputter Yields of Boron Nitride due to Xenon Ion Bombardment (Preprint)

2008 ◽  
Author(s):  
James L. Topper ◽  
Binyamin Rubin ◽  
Cody C. Farnell ◽  
Azer P. Yalin
Keyword(s):  
Boron Nitride ◽  
Ion Bombardment ◽  
Low Energy ◽  
Preliminary Results

scholarly journals First-Principles Identification of Single Photon Emitters Based on Carbon Clusters in Hexagonal Boron Nitride

2021 ◽  
Vol 125 (6) ◽  
pp. 1325-1335 ◽  
Author(s):  
Cesar Jara ◽  
Tomáš Rauch ◽  
Silvana Botti ◽  
Miguel A. L. Marques ◽  
Ariel Norambuena ◽  
...  
Keyword(s):  
Boron Nitride ◽  
First Principles ◽  
Single Photon ◽  
Hexagonal Boron Nitride ◽  
Carbon Clusters ◽  
Single Photon Emitters

scholarly journals Spurious poles in the scattering of electric and magnetic charges

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
John Terning ◽  
Christopher B. Verhaaren
Keyword(s):  
Perturbation Theory ◽  
Scattering Amplitudes ◽  
Pair Production ◽  
Magnetic Particles ◽  
Single Photon ◽  
Low Energy ◽  
Magnetic Interactions ◽  
Parity Conservation ◽  
Non Local ◽  
The Way

Abstract Theories with both electric and magnetic charges (“mutually non-local” theories) have several major obstacles to calculating scattering amplitudes. Even when the interaction arises through the kinetic mixing of two, otherwise independent, U(1)’s, so that all low-energy interactions are perturbative, difficulties remain: using a self-dual, local formalism leads to spurious poles at any finite order in perturbation theory. Correct calculations must show how the spurious poles cancel in observable scattering amplitudes. Consistency requires that one type of charge is confined as a result of one of the U(1)’s being broken. Here we show how the constraints of confinement and parity conservation on observable processes manages to cancel the spurious poles in scattering and pair production amplitudes, paving the way for systematic studies of the experimental signatures of “dark” electric-magnetic processes. Along the way we demonstrate some novel effects in electric-magnetic interactions, including that the amplitude for single photon production of magnetic particles by electric particles vanishes.

scholarly journals Radiative properties of quantum emitters in boron nitride from excited state calculations and Bayesian analysis

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Shiyuan Gao ◽  
Hsiao-Yi Chen ◽  
Marco Bernardi
Keyword(s):  
Boron Nitride ◽  
Density Functional ◽  
Single Photon ◽  
Radiative Lifetime ◽  
Radiative Properties ◽  
Data Set ◽  
Radiative Lifetimes ◽  
Emission Energy ◽  
Single Photon Emitters ◽  
Quantum Emitters

AbstractPoint defects in hexagonal boron nitride (hBN) have attracted growing attention as bright single-photon emitters. However, understanding of their atomic structure and radiative properties remains incomplete. Here we study the excited states and radiative lifetimes of over 20 native defects and carbon or oxygen impurities in hBN using ab initio density functional theory and GW plus Bethe-Salpeter equation calculations, generating a large data set of their emission energy, polarization and lifetime. We find a wide variability across quantum emitters, with exciton energies ranging from 0.3 to 4 eV and radiative lifetimes from ns to ms for different defect structures. Through a Bayesian statistical analysis, we identify various high-likelihood charge-neutral defect emitters, among which the native VNNB defect is predicted to possess emission energy and radiative lifetime in agreement with experiments. Our work advances the microscopic understanding of hBN single-photon emitters and introduces a computational framework to characterize and identify quantum emitters in 2D materials.

scholarly journals Unravelling a Zigzag Pathway for Hot Carrier Collection with Graphene Electrode

2021 ◽  
pp. 2886-2891
Author(s):  
Jin Zhang ◽  
Hao Hong ◽  
Jincan Zhang ◽  
Chunchun Wu ◽  
Hailin Peng ◽  
...  
Keyword(s):  
Hot Carrier ◽  
Graphene Electrode ◽  
Carrier Collection

scholarly journals An ultrastable and robust single-photon emitter in hexagonal boron nitride

2020 ◽  
Vol 124 ◽  
pp. 114251
Author(s):  
Wei Liu ◽  
Yi-Tao Wang ◽  
Zhi-Peng Li ◽  
Shang Yu ◽  
Zhi-Jin Ke ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Single Photon ◽  
Hexagonal Boron Nitride

scholarly journals The MicroBooNE Single-Photon Low-Energy Excess Search

2020 ◽  
Author(s):  
Sowjanya Gollapinni ◽  
Georgia Karagiorgi ◽  
Mark Lonegran ◽  
William Louis ◽  
Richard Van De Water ◽  
...  
Keyword(s):  
Single Photon ◽  
Low Energy ◽  
Energy Excess
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