Dynamical Evolution of Anisotropic Response in Black Phosphorus under Ultrafast Photoexcitation

Abstract

Black phosphorus has recently emerged as a promising material for high-performance electronic and optoelectronic device for its high mobility, tunable mid-infrared bandgap, and anisotropic electronic properties. Dynamical evolution of photoexcited carriers and the induced transient change of electronic properties are critical for materials' high-field performance but remain to be explored for black phosphorus. In this work, we perform angle-resolved transient reflection spectroscopy to study the dynamical evolution of anisotropic properties of black phosphorus under photoexcitation. We find that the anisotropy of reflectivity is enhanced in the pump-induced quasi-equilibrium state, suggesting an extraordinary enhancement of the anisotropy in dynamical conductivity in hot carrier dominated regime. These results raise attractive possibilities of creating high-field, angle-sensitive electronic, optoelectronic, and remote sensing devices exploiting the dynamical electronic anisotropy with black phosphorus.

On the Quantum Spin Hall Gap of Monolayer 1T′‐WTe2

“…The results show that although the amplitude of the signal has polarization angle dependence, the decay dynamics shows no dependence on pump-probe polarization similar to that observed in black phosphorus [34] . Therefore, in the subsequent measurements of the thickness dependent decay dynamics, crystal alignment with respect to the pump-probe polarization is not recorded.…”

Emerging Trends in Phosphorene Fabrication towards Next Generation Devices

“…BP single crystals larger than 1 cm were crystallized in the form of flakes at the cold end of the ampoule. The low‐pressure route, with the use of a mineralizer as the reaction promoter, was of interest because of its high yield in non‐toxic experimental conditions 112, 113, 114, 121, 122, 123. The red phosphorus, converted to BP by SnI 4 mineralization, gives red phosphorus and Au as its byproducts 113, 124…”

“…The mechanical exfoliation (ME) technique is widely adopted in the fabrication of BP 105, 121, 127, 128, 129. Because of its simplicity and ability to produce high‐quality materials, this technique was first utilized in the fabrication of graphene, and it is also growing to be more attractive for the synthesis of other 2D materials (much earlier for MoS 2 ) that are different from their bulk forms 130, 131, 132, 133, 134.…”

Onset of exciton-exciton annihilation in single-layer black phosphorus

“…As atomically thin black phosphorus has been successfully isolated only recently, very little is currently known about the carrier dynamics. Using pump-probe measurements, the evolution of exciton dynamics has been investigated, focusing on the in-plane anisotropy [33][34][35]. Most experiments have been performed at room temperature, and on thick samples [33], where the many-body effects are detrimentally weakened when compared to what is expected at low temperature on single atomic layers.…”

“…Using pump-probe measurements, the evolution of exciton dynamics has been investigated, focusing on the in-plane anisotropy [33][34][35]. Most experiments have been performed at room temperature, and on thick samples [33], where the many-body effects are detrimentally weakened when compared to what is expected at low temperature on single atomic layers. One study reports the temporal evolution of the PL of single-layer black phosphorus, investigated over a limited range of excitation powers, always in the low excitation regime, with a single exponential PL decay [27].…”