Band Gap Renormalization, Carrier Multiplication, and Stark Broadening in Photoexcited Black Phosphorus

Chen, Zhe‐Sheng; Dong, Jinwei; Papalazarou, E.; Marsi, M.; Giorgetti, C.; Zhang, Zailan; Tian, Bingbing; Rueff, Jean‐Pascal; Taleb‐Ibrahimi, A.; Perfetti, L.

doi:10.1021/acs.nanolett.8b04344

Cited by 30 publications

(52 citation statements)

References 30 publications

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“…First, in the experiment the photoexcitation occurs with a finite duration of about 50 fs and the total time resolution of our experiment is 100 fs, well above this timescale. Second, it has been demonstrated in the pristine BP case that a fast transient broadening of the VB happens in the first ps after the photoexcitation [60]. This effect is still present in the K-doped case [37] and explain the very fast increase of intensity in Fig.…”

Section: Namementioning

confidence: 83%

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Ultrafast dynamics of the surface photovoltage in potassium-doped black phosphorus

et al. 2021

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Black phosphorus is a quasi-two-dimensional layered semiconductor with a narrow direct band gap of 0.3 eV. A giant surface Stark effect can be produced by the potassium doping of black phosphorus, leading to a semiconductor to semimetal phase transition originating from the creation of a strong surface dipole and associated band bending. By using time-and angle-resolved photoemission spectroscopy, we report the partial photoinduced screening of this band bending by the creation of a compensating surface photovoltage. We further resolve the detailed dynamics of this effect at the pertinent timescales and the related evolution of the band structure near the Fermi level. We demonstrate that after a fast rise time, the surface photovoltage exhibits a plateau over a few tens of picoseconds before decaying on the nanosecond timescale. We support our experimental results with simulations based on drift-diffusion equations.

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Section: Namementioning

confidence: 83%

“…9. Nevertheless, it is more convenient to work along the ZZ line because the CB has no spectral weight at the normal emission along the AC direction due to matrix element effects [60]. The EDCs in Fig.…”

Section: B Dynamics Of the Surface Photovoltage In K-doped Black Phosphorusmentioning

confidence: 99%

Ultrafast dynamics of the surface photovoltage in potassium-doped black phosphorus

et al. 2021

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“…In addition, by using the same method, we transiently occupied the conduction band of black phosphorus by an ultrafast pump pulse and measured the gap value with a subsequent probe pulse. The negligible band gap renormalization and Stark broadening have been observed and explained [10].…”

Section: Introductionmentioning

confidence: 88%

“…For example, in indirect band gap semiconductors, the radiation recombination is far slower compared to direct band gap, as the absorption or emission of phonons need to be involved in the process, which is not suitable for light emission devices [7,8]. In anisotropic semiconductors such as black phosphorus, the dispersions of conductions band along each high symmetric directions are significantly different, which corresponds to giant electron effective mass differences, and the mobility is highly direction dependent [9,10].…”

Section: Introductionmentioning

confidence: 99%

Ultrafast dynamics with time-resolved ARPES: photoexcited electrons in monochalcogenide semiconductors

Chen¹,

Caillaux²,

Zhang³

et al. 2021

Comptes Rendus. Physique

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Time-resolved ARPES makes it possible to directly visualize the band dispersion of photoexcited solids, as well as to study its time evolution on the femtosecond time scale. In this article, we show how this technique can be used to monitor the ultrafast hot carrier dynamics and the conduction band dispersion in two typical monochalcogenide semiconductors: direct band gap, n-type indium selenide and indirect band gap, p-type germanium selenide. With this approach, one can directly estimate the effective electron masses of these semiconductors. Moreover, the dynamics of hot electrons in the two semiconductors are analyzed and compared. Our findings provide valuable information for the use of monochalcogenide semiconductors in future optoelectronic devices.

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“…The electronic state and distribution function of hot electrons in the accumulation layer is directly monitored by time and angle resolved photoelectron spectroscopy (tr-ARPES). Our approach offers exceptional advantages such as: i) the probing depth is comparable to the localization length of the quasi-2DEG 20 ; ii) the momentum selectivity reveals if excited electrons are in extended bulk states or in confined 2D states 21 ; iii) the electronic distribution discriminates between the classical and quantum regime of hot carriers; iv) the electronic cooling is slower than the typical pulse duration of mode-locked laser pulses 18,[22][23][24] . By monitoring all relevant parameters, the tr-ARPES data allow for an extraction of the experimental cooling rate and for a direct comparison with model calculations of screened Fröhlich interaction.…”

Section: Pacs Numbersmentioning

confidence: 99%

Ultrafast dynamics of hot carriers in a quasi–two-dimensional electron gas on InSe

Chen

Sjakste

Dong

et al. 2020

Proc. Natl. Acad. Sci. U.S.A.

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Two-dimensional electron gases (2DEGs) are at the base of current nanoelectronics because of their exceptional mobilities. Often the accumulation layer forms at polar interfaces with longitudinal optical (LO) modes. In most cases, the many-body screening of the quasi-2DEGs dramatically reduces the Fröhlich scattering strength. Despite the effectiveness of such a process, it has been recurrently proposed that a remote coupling with LO phonons persists even at high carrier concentration. We address this issue by perturbing electrons in an accumulation layer via an ultrafast laser pulse and monitoring their relaxation via time- and momentum-resolved spectroscopy. The cooling rate of excited carriers is monitored at doping level spanning from the semiconducting to the metallic limit. We observe that screening of LO phonons is not as efficient as it would be in a strictly 2D system. The large discrepancy is due to the remote coupling of confined states with the bulk. Our data indicate that the effect of such a remote coupling can be mimicked by a 3D Fröhlich interaction with Thomas–Fermi screening. These conclusions are very general and should apply to field effect transistors (FET) with high-κ dielectric gates, van der Waals heterostructures, and metallic interfaces between insulating oxides.

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Band Gap Renormalization, Carrier Multiplication, and Stark Broadening in Photoexcited Black Phosphorus

Cited by 30 publications

References 30 publications

Ultrafast dynamics of the surface photovoltage in potassium-doped black phosphorus

Ultrafast dynamics of the surface photovoltage in potassium-doped black phosphorus

Ultrafast dynamics with time-resolved ARPES: photoexcited electrons in monochalcogenide semiconductors

Ultrafast dynamics of hot carriers in a quasi–two-dimensional electron gas on InSe

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