scholarly journals Interface defect-assisted phonon scattering of hot carriers in graphene

2017 ◽  
Vol 96 (7) ◽  
Author(s):  
Sergey G. Menabde ◽  
Hyunwoo Cho ◽  
Namkyoo Park
Keyword(s):  
Phonon Scattering ◽  
Hot Carriers ◽  
Interface Defect

Hot carriers and excitation of Si/SiOx interface defect photoluminescence in Si nanocrystallites

2003 ◽  
Vol 340-342 ◽  
pp. 1113-1118 ◽  
Author(s):  
T.V. Torchynska ◽  
A. Diaz Cano ◽  
M. Morales Rodriguez ◽  
L.Yu. Khomenkova
Keyword(s):  
Hot Carriers ◽  
Interface Defect ◽  
Si Nanocrystallites

scholarly journals Hot Carriers in CVD-Grown Graphene Device with a Top h-BN Layer

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
C. Chuang ◽  
M. Mineharu ◽  
N. Matsumoto ◽  
M. Matsunaga ◽  
C.-W. Liu ◽  
...  
Keyword(s):  
Phonon Scattering ◽  
Average Rate ◽  
Relaxation Times ◽  
Energy Relaxation ◽  
Heat Diffusion ◽  
Multilayer Graphene ◽  
Hot Carriers ◽  
Conductance Fluctuations ◽  
Carrier Temperature ◽  
Grown Graphene

We investigate the energy relaxation of hot carriers in a CVD-grown graphene device with a top h-BN layer by driving the devices into the nonequilibrium regime. By using the magnetic field dependent conductance fluctuations of our graphene device as a self-thermometer, we can determine the effective carrier temperature Te at various driving currents I while keeping the lattice temperature TL fixed. Interestingly, it is found that Te is proportional to I, indicating little electron-phonon scattering in our device. Furthermore the average rate of energy loss per carrier Pe is proportional to (Te 2-TL 2), suggesting the heat diffusion rather than acoustic phonon processes in our system. The long energy relaxation times due to the weak electron-phonon coupling in CVD graphene capped with h-BN layer as well as in exfoliated multilayer graphene can find applications in hot carrier graphene-based devices.

Role of interface defect in hot carriers extraction at graphene-metal contact

2018 ◽  
Author(s):  
Sergey G. Menabde ◽  
Min Seok Jang ◽  
Ju Yeong Kim ◽  
Sung Yoon Min
Keyword(s):  
Metal Contact ◽  
Hot Carriers ◽  
Interface Defect

scholarly journals Ab initio study of hot electrons in GaAs

2015 ◽  
Vol 112 (17) ◽  
pp. 5291-5296 ◽  
Author(s):  
Marco Bernardi ◽  
Derek Vigil-Fowler ◽  
Chin Shen Ong ◽  
Jeffrey B. Neaton ◽  
Steven G. Louie
Keyword(s):  
Ab Initio ◽  
Phonon Scattering ◽  
Carrier Dynamics ◽  
Hot Electrons ◽  
Hot Electron ◽  
Hot Carriers ◽  
Hot Carrier ◽  
Acoustic Modes ◽  
Decay Times ◽  
Electron Phonon Scattering

Hot carrier dynamics critically impacts the performance of electronic, optoelectronic, photovoltaic, and plasmonic devices. Hot carriers lose energy over nanometer lengths and picosecond timescales and thus are challenging to study experimentally, whereas calculations of hot carrier dynamics are cumbersome and dominated by empirical approaches. In this work, we present ab initio calculations of hot electrons in gallium arsenide (GaAs) using density functional theory and many-body perturbation theory. Our computed electron–phonon relaxation times at the onset of the Γ, L, and X valleys are in excellent agreement with ultrafast optical experiments and show that the ultrafast (tens of femtoseconds) hot electron decay times observed experimentally arise from electron–phonon scattering. This result is an important advance to resolve a controversy on hot electron cooling in GaAs. We further find that, contrary to common notions, all optical and acoustic modes contribute substantially to electron–phonon scattering, with a dominant contribution from transverse acoustic modes. This work provides definitive microscopic insight into hot electrons in GaAs and enables accurate ab initio computation of hot carriers in advanced materials.

QUANTUM CASCADE NANOSTRUCTURES UNDER HIGH MAGNETIC FIELD

2009 ◽  
Vol 23 (12n13) ◽  
pp. 2861-2866
Author(s):  
N. PÉRÉ-LAPERNE ◽  
L. A. DE VAULCHIER ◽  
Y. GULDNER ◽  
C. SIRTORI ◽  
V. BERGER
Keyword(s):  
Magnetic Field ◽  
High Magnetic Field ◽  
Dark Current ◽  
Phonon Scattering ◽  
Interface Roughness ◽  
Landau Levels ◽  
Hot Carriers ◽  
Quantum Cascade ◽  
Transport Measurements ◽  
Quantum Cascade Structures

Magneto-transport measurements have been performed on two quantum cascade structures, a laser and a detector. These experiments lead to determine the different scattering processes involved in these devices. In the lasers we find both an interface roughness mechanism and LO-phonon scattering of hot carriers in the upper state's Landau levels. In detectors we discover that an inelastic mechanism increase the dark current whereas an elastic one limits the detectivity.

Towards quantitative simulations of inelastic electron diffraction patterns and images

1992 ◽  
Vol 50 (2) ◽  
pp. 1170-1171
Author(s):  
Z. L. Wang
Keyword(s):  
Phonon Scattering ◽  
Incident Beam ◽  
Dynamical Theory ◽  
Inelastic Electron ◽  
Additional Advantage ◽  
Coupled Equations ◽  
Atomic Vibrations ◽  
Diffraction Patterns ◽  
Primary Advantage ◽  
The One

A new dynamical theory has been developed based on Yoshioka's coupled equations for describing inelastic electron scattering in thin crystals. Compared to existing theories, the primary advantage of this theory is that the incoherent summation of the diffracted intensities contributed by electrons after exciting vast numbers of different excited states has been evaluated before any numerical calculation. An additional advantage is that the phase correlations of atomic vibrations are considered, so that full lattice dynamics can be combined in the phonon scattering calculation. The new theory has been proven to be equivalent to the inelastic multislice theory, and has been applied to calculate energy-filtered diffraction patterns and images formed by phonon, single electron and valence scattered electrons.A calculated diffraction pattern of elastic and phonon scattered electrons for a parallel incident beam case is in agreement with the one observed (Fig. 1), showing thermal diffuse scattering (TDS) streaks and Kikuchi pattern.

SH-Wave Scattering From the Interface Defect

2017 ◽  
Vol 5 (1) ◽  
pp. 45-50
Author(s):  
Myron Voytko ◽  
◽  
Yaroslav Kulynych ◽  
Dozyslav Kuryliak
Keyword(s):  
Half Space ◽  
Wave Diffraction ◽  
Scattered Field ◽  
Wave Scattering ◽  
Elastic Layer ◽  
Analytical Form ◽  
Structure Parameters ◽  
Sh Wave ◽  
Interface Defect ◽  
Hopf Method

The problem of the elastic SH-wave diffraction from the semi-infinite interface defect in the rigid junction of the elastic layer and the half-space is solved. The defect is modeled by the impedance surface. The solution is obtained by the Wiener- Hopf method. The dependences of the scattered field on the structure parameters are presented in analytical form. Verifica¬tion of the obtained solution is presented.

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