1
|
Zheng F, Wang LW. Multiple k-Point Nonadiabatic Molecular Dynamics for Ultrafast Excitations in Periodic Systems: The Example of Photoexcited Silicon. PHYSICAL REVIEW LETTERS 2023; 131:156302. [PMID: 37897744 DOI: 10.1103/physrevlett.131.156302] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 03/22/2023] [Accepted: 08/18/2023] [Indexed: 10/30/2023]
Abstract
With the rapid development of ultrafast experimental techniques for the research of carrier dynamics in solid-state systems, a microscopic understanding of the related phenomena, particularly a first-principle calculation, is highly desirable. Nonadiabatic molecular dynamics (NAMD) offers a real-time direct simulation of the carrier transfer or carrier thermalization. However, when applied to a periodic supercell, there is no cross-k-point transitions during the NAMD simulation. This often leads to a significant underestimation of the transition rate with the single-k-point band structure in a supercell. In this work, based on the surface hopping scheme used for NAMD, we propose a practical method to enable the cross-k transitions for a periodic system. We demonstrate our formalism by showing that the hot electron thermalization process by the multi-k-point NAMD in a small silicon supercell is equivalent to such simulation in a large supercell with a single Γ point. The simulated hot carrier thermalization process of the bulk silicon is compared with the recent ultrafast experiments, which shows excellent agreements. We have also demonstrated our method for the hot carrier coolings in the amorphous silicons and the GaAlAs_{2} solid solutions with the various cation distributions.
Collapse
Affiliation(s)
- Fan Zheng
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Lin-Wang Wang
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Science, Beijing 100083, China
| |
Collapse
|
2
|
Giri A, Walton SG, Tomko J, Bhatt N, Johnson MJ, Boris DR, Lu G, Caldwell JD, Prezhdo OV, Hopkins PE. Ultrafast and Nanoscale Energy Transduction Mechanisms and Coupled Thermal Transport across Interfaces. ACS NANO 2023; 17:14253-14282. [PMID: 37459320 PMCID: PMC10416573 DOI: 10.1021/acsnano.3c02417] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 06/06/2023] [Indexed: 08/09/2023]
Abstract
The coupled interactions among the fundamental carriers of charge, heat, and electromagnetic fields at interfaces and boundaries give rise to energetic processes that enable a wide array of technologies. The energy transduction among these coupled carriers results in thermal dissipation at these surfaces, often quantified by the thermal boundary resistance, thus driving the functionalities of the modern nanotechnologies that are continuing to provide transformational benefits in computing, communication, health care, clean energy, power recycling, sensing, and manufacturing, to name a few. It is the purpose of this Review to summarize recent works that have been reported on ultrafast and nanoscale energy transduction and heat transfer mechanisms across interfaces when different thermal carriers couple near or across interfaces. We review coupled heat transfer mechanisms at interfaces of solids, liquids, gasses, and plasmas that drive the resulting interfacial heat transfer and temperature gradients due to energy and momentum coupling among various combinations of electrons, vibrons, photons, polaritons (plasmon polaritons and phonon polaritons), and molecules. These interfacial thermal transport processes with coupled energy carriers involve relatively recent research, and thus, several opportunities exist to further develop these nascent fields, which we comment on throughout the course of this Review.
Collapse
Affiliation(s)
- Ashutosh Giri
- Department
of Mechanical, Industrial and Systems Engineering, University of Rhode Island, Kingston, Rhode Island 02881, United States
| | - Scott G. Walton
- Plasma
Physics Division, Naval Research Laboratory, Washington, DC 22032, United States
| | - John Tomko
- Department
of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, Virginia 22904, United States
| | - Niraj Bhatt
- Department
of Mechanical, Industrial and Systems Engineering, University of Rhode Island, Kingston, Rhode Island 02881, United States
| | - Michael J. Johnson
- Plasma
Physics Division, Naval Research Laboratory, Washington, DC 22032, United States
| | - David R. Boris
- Plasma
Physics Division, Naval Research Laboratory, Washington, DC 22032, United States
| | - Guanyu Lu
- Department
of Mechanical Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Joshua D. Caldwell
- Department
of Mechanical Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
- Interdisciplinary
Materials Science, Vanderbilt University, Nashville, Tennessee 37235, United States
- Vanderbilt
Institute of Nanoscale Science and Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Oleg V. Prezhdo
- Department
of Chemistry, University of Southern California, Los Angeles, California 90089, United States
- Department
of Physics and Astronomy, University of
Southern California, Los Angeles, California 90089, United States
| | - Patrick E. Hopkins
- Department
of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, Virginia 22904, United States
- Department
of Materials Science and Engineering, University
of Virginia, Charlottesville, Virginia 22904, United States
- Department
of Physics, University of Virginia, Charlottesville, Virginia 22904, United States
| |
Collapse
|
3
|
Li W, Xue T, Mora-Perez C, Prezhdo OV. Ab initio quantum dynamics of plasmonic charge carriers. TRENDS IN CHEMISTRY 2023. [DOI: 10.1016/j.trechm.2023.02.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/19/2023]
|
4
|
Lu TF, Agrawal S, Tokina M, Chu W, Hirt D, Hopkins PE, Prezhdo OV. Control of Charge Carrier Relaxation at the Au/WSe 2 Interface by Ti and TiO 2 Adhesion Layers: Ab Initio Quantum Dynamics. ACS APPLIED MATERIALS & INTERFACES 2022; 14:57197-57205. [PMID: 36516838 DOI: 10.1021/acsami.2c18793] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Phonon-mediated charge relaxation plays a vital role in controlling thermal transport across an interface for efficient functioning of two-dimensional (2D) nanostructured devices. Using a combination of nonadiabatic molecular dynamics with real-time time-dependent density functional theory, we demonstrate a strong influence of adhesion layers at the Au/WSe2 interface on nonequilibrium charge relaxation, rationalizing recent ultrafast time-resolved experiments. Ti oxide layers (TiOx) create a barrier to the interaction between Au and WSe2 and extend hot carrier lifetimes, creating benefits for photovoltaic and photocatalytic applications. In contrast, a metallic Ti layer accelerates the energy flow, as needed for efficient heat dissipation in electronic devices. The interaction of metallic Ti with WSe2 causes W-Se bond scissoring and pins the Fermi level. The Ti adhesion layer enhances the electron-phonon coupling due to an increased density of states and the light mass of the Ti atom. The conclusions are robust to presence of typical point defects. The atomic-scale ab initio analysis of carrier relaxation at the interfaces advances our knowledge in fabricating nanodevices with optimized electronic and thermal properties.
Collapse
Affiliation(s)
- Teng-Fei Lu
- School of Materials Science and Engineering, Dalian Jiaotong University, Dalian 116028, Liaoning Province, China
| | - Sraddha Agrawal
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Marina Tokina
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Weibin Chu
- Key Laboratory of Computational Physical Sciences (Ministry of Education), Institute of Computational Physical Sciences, Fudan University, Shanghai 200433, People's Republic of China
| | - Daniel Hirt
- Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, Virginia 22904, United States
| | - Patrick E Hopkins
- Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, Virginia 22904, United States
- Department of Materials Science and Engineering, University of Virginia, Charlottesville, Virginia 22904, United States
- Department of Physics, University of Virginia, Charlottesville, Virginia 22904, United States
| | - Oleg V Prezhdo
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
- Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089, United States
| |
Collapse
|
5
|
Aryana K, Zhang Y, Tomko JA, Hoque MSB, Hoglund ER, Olson DH, Nag J, Read JC, Ríos C, Hu J, Hopkins PE. Suppressed electronic contribution in thermal conductivity of Ge 2Sb 2Se 4Te. Nat Commun 2021; 12:7187. [PMID: 34893593 PMCID: PMC8664948 DOI: 10.1038/s41467-021-27121-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 10/28/2021] [Indexed: 11/27/2022] Open
Abstract
Integrated nanophotonics is an emerging research direction that has attracted great interests for technologies ranging from classical to quantum computing. One of the key-components in the development of nanophotonic circuits is the phase-change unit that undergoes a solid-state phase transformation upon thermal excitation. The quaternary alloy, Ge2Sb2Se4Te, is one of the most promising material candidates for application in photonic circuits due to its broadband transparency and large optical contrast in the infrared spectrum. Here, we investigate the thermal properties of Ge2Sb2Se4Te and show that upon substituting tellurium with selenium, the thermal transport transitions from an electron dominated to a phonon dominated regime. By implementing an ultrafast mid-infrared pump-probe spectroscopy technique that allows for direct monitoring of electronic and vibrational energy carrier lifetimes in these materials, we find that this reduction in thermal conductivity is a result of a drastic change in electronic lifetimes of Ge2Sb2Se4Te, leading to a transition from an electron-dominated to a phonon-dominated thermal transport mechanism upon selenium substitution. In addition to thermal conductivity measurements, we provide an extensive study on the thermophysical properties of Ge2Sb2Se4Te thin films such as thermal boundary conductance, specific heat, and sound speed from room temperature to 400 °C across varying thicknesses.
Collapse
Affiliation(s)
- Kiumars Aryana
- Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA, 22904, USA
| | - Yifei Zhang
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - John A Tomko
- Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA, 22904, USA
| | - Md Shafkat Bin Hoque
- Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA, 22904, USA
| | - Eric R Hoglund
- Department of Materials Science and Engineering, University of Virginia, Charlottesville, VA, 22904, USA
| | - David H Olson
- Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA, 22904, USA
| | - Joyeeta Nag
- Western Digital Corporation, San Jose, CA, 95119, USA
| | - John C Read
- Western Digital Corporation, San Jose, CA, 95119, USA
| | - Carlos Ríos
- Department of Materials Science and Engineering, University of Maryland, College Park, MD, 20742, USA
- Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, MD, 20742, USA
| | - Juejun Hu
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Patrick E Hopkins
- Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA, 22904, USA.
- Department of Materials Science and Engineering, University of Virginia, Charlottesville, VA, 22904, USA.
- Department of Physics, University of Virginia, Charlottesville, VA, 22904, USA.
| |
Collapse
|
6
|
Smith B, Shakiba M, Akimov AV. Nonadiabatic Dynamics in Si and CdSe Nanoclusters: Many-Body vs Single-Particle Treatment of Excited States. J Chem Theory Comput 2021; 17:678-693. [DOI: 10.1021/acs.jctc.0c01009] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Brendan Smith
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260 United States
| | - Mohammad Shakiba
- Department of Materials Science and Engineering, Shahid Bahonar University of Kerman, Kerman 76169-14111, Iran
| | - Alexey V. Akimov
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260 United States
| |
Collapse
|
7
|
Tomko JA, Runnerstrom EL, Wang YS, Chu W, Nolen JR, Olson DH, Kelley KP, Cleri A, Nordlander J, Caldwell JD, Prezhdo OV, Maria JP, Hopkins PE. Long-lived modulation of plasmonic absorption by ballistic thermal injection. NATURE NANOTECHNOLOGY 2021; 16:47-51. [PMID: 33169011 DOI: 10.1038/s41565-020-00794-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 10/13/2020] [Indexed: 06/11/2023]
Abstract
Light-matter interactions that induce charge and energy transfer across interfaces form the foundation for photocatalysis1,2, energy harvesting3 and photodetection4, among other technologies. One of the most common mechanisms associated with these processes relies on carrier injection. However, the exact role of the energy transport associated with this hot-electron injection remains unclear. Plasmon-assisted photocatalytic efficiencies can improve when intermediate insulation layers are used to inhibit the charge transfer5,6 or when off-resonance excitations are employed7, which suggests that additional energy transport and thermal effects could play an explicit role even if the charge transfer is inhibited8. This provides an additional interfacial mechanism for the catalytic and plasmonic enhancement at interfaces that moves beyond the traditionally assumed physical charge injection9-12. In this work, we report on a series of ultrafast plasmonic measurements that provide a direct measure of electronic distributions, both spatially and temporally, after the optical excitation of a metal/semiconductor heterostructure. We explicitly demonstrate that in cases of strong non-equilibrium, a novel energy transduction mechanism arises at the metal/semiconductor interface. We find that hot electrons in the metal contact transfer their energy to pre-existing free electrons in the semiconductor, without an equivalent spatiotemporal transfer of charge. Further, we demonstrate that this ballistic thermal injection mechanism can be utilized as a unique means to modulate plasmonic interactions. These experimental results are well-supported by both rigorous multilayer optical modelling and first-principle ab initio calculations.
Collapse
Affiliation(s)
- John A Tomko
- Department of Materials Science and Engineering, University of Virginia, Charlottesville, VA, USA
| | - Evan L Runnerstrom
- Army Research Office, CCDC US Army Research Laboratory, Research Triangle Park, NC, USA
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC, USA
| | - Yi-Siang Wang
- Department of Chemistry, University of Southern California, Los Angeles, CA, USA
- Department of Physics and Astronomy, University of Southern California, Los Angeles, CA, USA
| | - Weibin Chu
- Department of Chemistry, University of Southern California, Los Angeles, CA, USA
- Department of Physics and Astronomy, University of Southern California, Los Angeles, CA, USA
| | - Joshua R Nolen
- Institute of Nanoscale Science and Engineering, Vanderbilt University, Nashville, TN, USA
| | - David H Olson
- Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA, USA
| | - Kyle P Kelley
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC, USA
| | - Angela Cleri
- Department of Materials Science and Engineering, Pennsylvania State University, State College, PA, USA
| | - Josh Nordlander
- Department of Materials Science and Engineering, Pennsylvania State University, State College, PA, USA
| | - Joshua D Caldwell
- Institute of Nanoscale Science and Engineering, Vanderbilt University, Nashville, TN, USA
| | - Oleg V Prezhdo
- Department of Chemistry, University of Southern California, Los Angeles, CA, USA
- Department of Physics and Astronomy, University of Southern California, Los Angeles, CA, USA
| | - Jon-Paul Maria
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC, USA
- Department of Materials Science and Engineering, Pennsylvania State University, State College, PA, USA
| | - Patrick E Hopkins
- Department of Materials Science and Engineering, University of Virginia, Charlottesville, VA, USA.
- Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA, USA.
- Department of Physics, University of Virginia, Charlottesville, VA, USA.
| |
Collapse
|
8
|
Wang YS, Nijjar P, Zhou X, Bondar DI, Prezhdo OV. Combining Lindblad Master Equation and Surface Hopping to Evolve Distributions of Quantum Particles. J Phys Chem B 2020; 124:4326-4337. [DOI: 10.1021/acs.jpcb.0c03030] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yi-Siang Wang
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Parmeet Nijjar
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Xin Zhou
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
- College of Environment and Chemical Engineering, Dalian University, Dalian 116622, P. R. China
| | - Denys I. Bondar
- Department of Physics and Engineering Physics, Tulane University, New Orleans, Louisiana 70118, United States
| | - Oleg V. Prezhdo
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
- Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089, United States
| |
Collapse
|
9
|
Lu TF, Wang YS, Tomko JA, Hopkins PE, Zhang HX, Prezhdo OV. Control of Charge Carrier Dynamics in Plasmonic Au Films by TiO x Substrate Stoichiometry. J Phys Chem Lett 2020; 11:1419-1427. [PMID: 32011143 DOI: 10.1021/acs.jpclett.9b03884] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Plasmonic excitations in noble metals have many fascinating properties and give rise to a broad range of applications. We demonstrate, using nonadiabatic molecular dynamics combined with time-domain density functional theory, that the chemical composition and stoichiometry of substrates can have a strong influence on charge dynamics. By changing oxygen content in TiO2, including stoichiometric, oxygen rich, and oxygen poor phases, and Ti metal, one can alter lifetimes of charge carriers in Au by a factor of 5 and control the ratio of electron-to-hole relaxation rates by a factor of 10. Remarkably, a thin TiOx substrate greatly alters charge carrier properties in much thicker Au films. Such large variations stem from the fact that the Ti and O atoms are much lighter than Au, and their vibrations are much faster at dissipating the energy. The control over a particular charge carrier and an energy range depends on the Au and TiOx level alignment, and the interfacial interaction strength. These factors are easily influenced by the TiOx stoichiometry. In particular, oxygen rich and poor TiO2 can be used to control holes and electrons, respectively, while metallic Ti affects both charge carriers. The detailed atomistic analysis of the interfacial and electron-vibrational interactions generates the fundamental understanding of the properties of plasmonic materials needed to design photovoltaic, photocatalytic, optoelectronic, sensing, nanomedical, and other devices.
Collapse
Affiliation(s)
- Teng-Fei Lu
- Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry , Jilin University , Changchun 130023 , People's Republic of China
- Department of Chemistry , University of Southern California , Los Angeles , California 90089 , United States
| | - Yi-Siang Wang
- Department of Chemistry , University of Southern California , Los Angeles , California 90089 , United States
| | - John A Tomko
- Department of Materials Science and Engineering , University of Virginia , Charlottesville , Virginia 22904 , United States
| | - Patrick E Hopkins
- Department of Materials Science and Engineering , University of Virginia , Charlottesville , Virginia 22904 , United States
- Department of Mechanical and Aerospace Engineering , University of Virginia , Charlottesville , Virginia 22904 , United States
- Department of Physics , University of Virginia , Charlottesville , Virginia 22904 , United States
| | - Hong-Xing Zhang
- Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry , Jilin University , Changchun 130023 , People's Republic of China
| | - Oleg V Prezhdo
- Department of Chemistry , University of Southern California , Los Angeles , California 90089 , United States
| |
Collapse
|
10
|
Zhang Z, Qiao L, Mora-Perez C, Long R, Prezhdo OV. Pb dimerization greatly accelerates charge losses in MAPbI3: Time-domain ab initio analysis. J Chem Phys 2020; 152:064707. [DOI: 10.1063/1.5131342] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Affiliation(s)
- Zhaosheng Zhang
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing 100875, People’s Republic of China
| | - Lu Qiao
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing 100875, People’s Republic of China
| | - Carlos Mora-Perez
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Run Long
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing 100875, People’s Republic of China
| | - Oleg V. Prezhdo
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| |
Collapse
|
11
|
Zheng F, Wang LW. Ultrafast Hot Carrier Injection in Au/GaN: The Role of Band Bending and the Interface Band Structure. J Phys Chem Lett 2019; 10:6174-6183. [PMID: 31538792 DOI: 10.1021/acs.jpclett.9b02402] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Plasmon photochemistry can potentially play a significant role in photocatalysis. To realize this potential, it is critical to enhance the plasmon excited hot carrier transfer and collection. However, the lack of atomistic understanding of the carrier transfer across the interface, especially when the carrier is still "hot", makes it challenging to design a more efficient system. In this work, we apply the nonadiabatic molecular dynamics simulation to study hot carrier dynamics in the system of a Au nanocluster on top of a GaN surface. By setting up the initial excited hole in Au, the carrier transfer from Au to GaN is found to be on a subpicosecond time scale. The hot hole first cools to the band edge of Au d-states while it transfers to GaN. After the hole has cooled down to the band edge of GaN, we find that some of the charges can return back to Au. By applying different external potentials to mimic the Schottky barrier band bending, the returning charge can be reduced, demonstrating the importance of the internal electric field. Finally, with the understanding of the carrier transfer's pathway, we suggest that a ZnO layer between GaN and Au can effectively block the "cold" carrier from returning back to Au but still allow the hot carrier to transfer from Au to GaN.
Collapse
Affiliation(s)
- Fan Zheng
- Joint Center for Artificial Photosynthesis and Materials Sciences Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Lin-Wang Wang
- Joint Center for Artificial Photosynthesis and Materials Sciences Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| |
Collapse
|