Ultrafast photoconductivity and terahertz vibrational dynamics in double-helix SnIP nanowires

Abstract

Tin iodide phosphide (SnIP), an inorganic double-helix material, is a quasi-1D van der Waals semiconductor that shows promise in photocatalysis and flexible electronics. However, our understanding of the fundamental photophysics and charge transport dynamics of this new material is limited. Here, we use time-resolved terahertz (THz) spectroscopy to probe the transient photoconductivity of SnIP nanowire films and, with insight into the highly anisotropic electronic structure from quantum chemical calculations, measure an electron mobility as high as 280 $c{m}^2{V}^{-1}{s}^{-1}$. Additionally, the THz vibrational spectrum reveals a photoexcitation-induced charge redistribution that reduces the amplitude of a twisting mode of the outer SnI helix on picosecond timescales. Finally, we show that the carrier lifetime and mobility are limited by a trap density greater than $10^{18}c{m}^{-3}$. Our results provide insight into the optical excitation and relaxation pathways of SnIP and demonstrate a remarkably high carrier mobility for such a soft and flexible material.

References in corpus (14)

• Raman spectroscopy as probe of nanometer-scale strain variations in graphene
• The transient localization scenario for charge transport in crystalline organic materials
• Analyzing the Carrier Mobility in Transition-metal Dichalcogenide MoS2 Field-effect Transistors
• One-dimensional van der Waals heterostructures
• Microscopic origin of the Drude-Smith model
• Elastic softness of hybrid lead halide perovskites
• Chasing the killer phonon mode for the rational design of low disorder, high mobility molecular semiconductors
• Intrinsic Charge Carrier Mobility in Single-Layer Black Phosphorus
• Ultrafast THz probe of photo-induced polarons in lead-halide perovskites
• Crossover from Super- to Sub-Diffusive Motion and Memory Effects in Crystalline Organic Semiconductors
• Faraday-cage screening reveals intrinsic aspects of the van der Waals attraction
• Phonon order and reststrahlen bands of polar vibrations in crystals with monoclinic symmetry
• Importance of van der Waals interaction on structural, vibrational, and thermodynamics properties of NaCl
• Many-body recombination in insulating cuprates