Amplitude-mode spectroscopy of chemically injected and photogenerated charge carriers in semiconducting single-walled carbon nanotubes

Vardeny, Shai R.; Phillips, Alan; Thurman, Kira A.; Vardeny, Z. Valy; Blackburn, Jeffrey L.

doi:10.1007/s12274-022-5080-1

Cited by 1 publication

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“…For example, a rich spectrum of observed Fano resonances likely results from coupling of the narrow vibrational transitions to the broad FCA continuum, as observed for, e.g., doped SWCNTs. 40 , 41 At higher energy, the cluster of vibrational peaks in pristine PEPI is modulated, resulting in a derivative-like feature as well as some absorption from the adsorbed BV dopant molecules on the surface ( Figure S3 ). In the visible/near-infrared spectral range, doping-induced absorption is also observed at energies just below the exciton absorption, indicating transitions from the valence band into ionized dopant levels energetically positioned in the gap close to the conduction band ( Figure S4 ).…”

Section: Resultsmentioning

confidence: 99%

Optical Studies of Doped Two-Dimensional Lead Halide Perovskites: Evidence for Rashba-Split Branches in the Conduction Band

Lafalce,

Bodin,

Larson

et al. 2024

ACS Nano

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Two-dimensional (2D) hybrid organic/inorganic perovskites are an emerging materials class for optoelectronic and spintronic applications due to strong excitonic absorption and emission, large spin− orbit coupling, and Rashba spin-splitting effects. For many of the envisioned applications, tuning the majority charge carrier (electron or hole) concentration is desirable, but electronic doping of metal-halide perovskites has proven to be challenging. Here, we demonstrate electron injection into the lower-energy branch of the Rashba-split conduction band of 2D phenethylammonium lead iodide by means of n-type molecular doping at room temperature. The molecular dopant, benzyl viologen (BV), is shown to compensate adventitious p-type impurities and can lead to a tunable Fermi level above the conduction band minimum and increased conductivity in intrinsic samples. The doping-induced carrier concentration is monitored by the observation of free-carrier absorption and intraband optical transitions in the infrared spectral range. These optical measurements allow for an estimation of the Rashba splitting energy E R ≈38 ± 4 meV. Photoinduced quantum beating measurements demonstrate that the excess electron density reduces the electron spin g-factor by ca. 6%. This work demonstrates controllable carrier concentrations in hybrid organic/inorganic perovskites and yields potential for room temperature spin control through the Rashba effect.

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Section: Resultsmentioning

confidence: 99%