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Generation of photocurrents in semiconducting materials requires dissociation of excitons into free charge carriers. While thermal agitation is sufficient to induce dissociation in most bulk materials, an additional push is required to…

Mesoscale and Nanoscale Physics · Physics 2019-07-24 Høgni C. Kamban , Thomas G. Pedersen

The two-dimensional character and reduced screening in monolayer transition-metal dichalcogenides (TMDs) lead to the ubiquitous formation of robust excitons with binding energies orders of magnitude larger than in bulk semiconductors.…

Materials Science · Physics 2017-09-26 Benedikt Scharf , Gaofeng Xu , Alex Matos-Abiague , Igor Žutić

Twisted transition metal dichalcogenides (TMDs) present an intriguing platform for exploring excitons and their transport properties. By introducing a twist angle, a moir\'e superlattice forms, providing a spatially dependent exciton energy…

Mesoscale and Nanoscale Physics · Physics 2024-01-17 Willy Knorr , Samuel Brem , Giuseppe Meneghini , Ermin Malic

We analyze the dielectric-function spectra of low dimensional transition metal dichalcogenides (TMDCs) using a fully analytical model of the complex dielectric function that is applicable in fractional dimensional space. We extract the…

Materials Science · Physics 2018-12-04 A. Thilagam

Transition metal dichalcogenide (TMD) monolayers (MLs) exhibit rich photoluminescence spectra associated with interband optical transitions of direct-gap semiconductors. Upon absorption of photons, direct excitons with zero center-of-mass…

The ultrathin transition metal dichalcogenides (TMDs) have emerged as promising materials for various applications using two dimensional (2D) semiconductors. They have attracted increasing attention due to their unique optical properties…

Mesoscale and Nanoscale Physics · Physics 2016-09-20 Aïda Hichri , Imen Ben Amara , Sabrine Ayari , Sihem Jaziri

Exciton binding energies of hundreds of meV and strong light absorption in the optical frequency range make transition metal dichalcogenides (TMDs) promising for novel optoelectronic nanodevices. In particular, atomically thin TMDs can be…

Mesoscale and Nanoscale Physics · Physics 2018-04-24 Simon Ovesen , Samuel Brem , Christopher Linderälv , Mikael Kuisma , Paul Erhart , Malte Selig , Ermin Malic

Transition metal dichalcogenides (TMDs) are known to support complex excitonic states. Revealing the differences in relaxation dynamics among different excitonic species and elucidating the transition dynamics between them may provide…

Mesoscale and Nanoscale Physics · Physics 2021-04-07 Anran Wang , Yuhan Wang , Jianfei Li , Ning Xu , Songlin Li , Xinran Wang , Yi Shi , Fengqiu Wang

Transition metal dichalcogenide (TMDC) monolayer has recently emerged as an important two-dimensional semiconductor with promising potentials for electronic and optoelectronic devices. Unlike semi-metallic graphene, layered TMDC has a…

Mesoscale and Nanoscale Physics · Physics 2014-10-16 Ziliang Ye , Ting Cao , Kevin O'Brien , Hanyu Zhu , Xiaobo Yin , Yuan Wang , Steven G. Louie , Xiang Zhang

We study theoretically the Coulomb interaction between excitons in transition metal dichalcogenide (TMD) monolayers. We calculate direct and exchange interaction for both ground and excited states of excitons. The screening of the Coulomb…

Mesoscale and Nanoscale Physics · Physics 2017-09-13 V. Shahnazaryan , I. Iorsh , I. A. Shelykh , O. Kyriienko

We study exciton radiative decay in a two-dimensional material, taking into account large thermal population in the non-radiative states, from which excitons are scattered into the radiative states by acoustic phonons. We find an analytical…

Mesoscale and Nanoscale Physics · Physics 2016-11-23 A. O. Slobodeniuk , D. M. Basko

The energy landscape of optical excitations in mono- and few-layer transition metal dichalcogenides (TMDs) is dominated by optically bright and dark excitons. These excitons can be fully localized within a single TMD layer, or the electron-…

Van der Waals heterostructures constitute a platform for investigating intriguing many-body quantum phenomena. In particular, transition-metal dichalcogenide (TMD) hetero-bilayers host long-lived interlayer excitons which exhibit permanent…

Mesoscale and Nanoscale Physics · Physics 2022-09-14 Daniel Erkensten , Samuel Brem , Raül Perea-Causin , Ermin Malic

van der Waals heterostructures consisting of vertically stacked transition-metal dichalcogenides (TMDs) exhibit a rich landscape of bright and dark intra- and interlayer excitons. In spite of a growing literature in this field of research,…

Mesoscale and Nanoscale Physics · Physics 2023-04-17 Joakim Hagel , Samuel Brem , Christopher Linderälv , Paul Erhart , Ermin Malic

Studies of excitonic transport in transition metal dichalcogenide monolayers have attracted increasing interest in recent years in order to develop nano-optoelectronic devices made with 2D materials. These studies began with low to moderate…

The dynamics of exciton formation in transition metal dichalcogenides is difficult to measure experimentally, since many momentum-indirect exciton states are not accessible to optical interband spectroscopy. Here, we combine a tuneable…

A rate equation model for the dark and bright excitons kinetics is proposed which explains the wide variation in the observed degree of circular polarization of the PL emission in different TMDs monolayers. Our work suggests that the dark…

Mesoscale and Nanoscale Physics · Physics 2017-01-18 M. Baranowski , A. Surrente , D. K. Maude , M Ballottin , A. A. Mitioglu , P. C. M. Christianen , Y. C. Kung , D. Dumcenco , A. Kis , P Plochocka

Since the seminal work on MoS2 monolayers, photoexcitation in atomically-thin transition metal dichalcogenides (TMDCs) has been assumed to result in excitons with large binding energies (~ 200-600 meV). Because the exciton binding energies…

It is widely comprehended that temperature may cause phonon-exciton scattering, enhancing the energy level's linewidth and leading to some spectrum shifts. However, in the present paper, we suggest a different mechanism that allows the…

Mesoscale and Nanoscale Physics · Physics 2023-04-11 Duy-Nhat Ly , Dai-Nam Le , Ngoc-Hung Phan , Van-Hoang Le

Van der Waals materials and heterostructures manifesting strongly bound room temperature exciton states exhibit emergent physical phenomena and are of a great promise for optoelectronic applications. Here, we demonstrate that nanostructured…