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Title: Electron–hole liquid in a van der Waals heterostructure photocell at room temperature

Abstract

In semiconductors, photo-excited charge carriers exist as a gas of electrons and holes, bound electron–hole pairs (excitons), biexcitons and trions. At sufficiently high densities, the non-equilibrium system of electrons (e-) and holes (h +) may merge into an electronic liquid droplet. Here, we report on the electron–hole liquid in ultrathin MoTe2 photocells revealed through multi-parameter dynamic photoresponse microscopy (MPDPM). By combining rich visualization with comprehensive analysis of very large data sets acquired through MPDPM, we find that ultrafast laser excitation at a graphene–MoTe 2–graphene interface leads to the abrupt formation of ring-like spatial patterns in the photocurrent response as a function of increasing optical power at T = 297 K. The sudden onset to these patterns, together with extreme sublinear power dependence and picosecond-scale photocurrent dynamics, provide strong evidence for the formation of a two-dimensional electron–hole liquid droplet. The electron–hole liquid, which features a macroscopic population of correlated electrons and holes, may offer a path to room-temperature optoelectronic devices that harness collective electronic phenomena.

Authors:
ORCiD logo; ORCiD logo; ; ORCiD logo
Publication Date:
Research Org.:
Energy Frontier Research Centers (EFRC) (United States). Spins and Heat in Nanoscale Electronic Systems (SHINES); Univ. of California, Riverside, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1566619
DOE Contract Number:  
SC0012670
Resource Type:
Journal Article
Journal Name:
Nature Photonics
Additional Journal Information:
Journal Volume: 13; Journal Issue: 4; Journal ID: ISSN 1749-4885
Publisher:
Nature Publishing Group
Country of Publication:
United States
Language:
English
Subject:
phonons, thermal conductivity, thermoelectric, spin dynamics, spintronics

Citation Formats

Arp, Trevor B., Pleskot, Dennis, Aji, Vivek, and Gabor, Nathaniel M. Electron–hole liquid in a van der Waals heterostructure photocell at room temperature. United States: N. p., 2019. Web. doi:10.1038/s41566-019-0349-y.
Arp, Trevor B., Pleskot, Dennis, Aji, Vivek, & Gabor, Nathaniel M. Electron–hole liquid in a van der Waals heterostructure photocell at room temperature. United States. doi:10.1038/s41566-019-0349-y.
Arp, Trevor B., Pleskot, Dennis, Aji, Vivek, and Gabor, Nathaniel M. Mon . "Electron–hole liquid in a van der Waals heterostructure photocell at room temperature". United States. doi:10.1038/s41566-019-0349-y.
@article{osti_1566619,
title = {Electron–hole liquid in a van der Waals heterostructure photocell at room temperature},
author = {Arp, Trevor B. and Pleskot, Dennis and Aji, Vivek and Gabor, Nathaniel M.},
abstractNote = {In semiconductors, photo-excited charge carriers exist as a gas of electrons and holes, bound electron–hole pairs (excitons), biexcitons and trions. At sufficiently high densities, the non-equilibrium system of electrons (e-) and holes (h+) may merge into an electronic liquid droplet. Here, we report on the electron–hole liquid in ultrathin MoTe2 photocells revealed through multi-parameter dynamic photoresponse microscopy (MPDPM). By combining rich visualization with comprehensive analysis of very large data sets acquired through MPDPM, we find that ultrafast laser excitation at a graphene–MoTe2–graphene interface leads to the abrupt formation of ring-like spatial patterns in the photocurrent response as a function of increasing optical power at T = 297 K. The sudden onset to these patterns, together with extreme sublinear power dependence and picosecond-scale photocurrent dynamics, provide strong evidence for the formation of a two-dimensional electron–hole liquid droplet. The electron–hole liquid, which features a macroscopic population of correlated electrons and holes, may offer a path to room-temperature optoelectronic devices that harness collective electronic phenomena.},
doi = {10.1038/s41566-019-0349-y},
journal = {Nature Photonics},
issn = {1749-4885},
number = 4,
volume = 13,
place = {United States},
year = {2019},
month = {2}
}

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