Tunable photogating in a molecular aggregate coupled graphene phototransistor

Fuente: arXiv
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Autores principales: Raina, Abhinav, Sanfilippo, Maurizio, Moon, Chang-Ki, Neubauer, Manuel, Meerholz, Klaus, Gather, Malte C., Lindfors, Klas
Formato: Preprint
Publicado: 2025
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author Raina, Abhinav
Sanfilippo, Maurizio
Moon, Chang-Ki
Neubauer, Manuel
Meerholz, Klaus
Gather, Malte C.
Lindfors, Klas
author_facet Raina, Abhinav
Sanfilippo, Maurizio
Moon, Chang-Ki
Neubauer, Manuel
Meerholz, Klaus
Gather, Malte C.
Lindfors, Klas
contents We present a graphene photodetector coupled to a layer of aggregated organic semiconductor. A graphene phototransistor is covered with a thin film of merocyanine molecules. The aggregation of the molecular layer can be controlled by the deposition parameters and post-deposition annealing to obtain films ranging from amorphous to a highly aggregated state. The molecular layer has a uniaxial structure with excitonic transitions whose transition dipole moments are well defined. The presence of the molecular layer results in an enormous increase in the response of the phototransistor. We further demonstrate that the signal-enhancement is due to p-photodoping of the graphene. The spectroscopic photoresponse suggests that the photodoping via monomers and molecular aggregates takes place differently. Our photodetector is a platform to study the influence of molecular aggregation and order on charge transport processes between aggregated organic semiconductors and two-dimensional materials.
format Preprint
id arxiv_https___arxiv_org_abs_2505_17232
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Tunable photogating in a molecular aggregate coupled graphene phototransistor
Raina, Abhinav
Sanfilippo, Maurizio
Moon, Chang-Ki
Neubauer, Manuel
Meerholz, Klaus
Gather, Malte C.
Lindfors, Klas
Mesoscale and Nanoscale Physics
Optics
We present a graphene photodetector coupled to a layer of aggregated organic semiconductor. A graphene phototransistor is covered with a thin film of merocyanine molecules. The aggregation of the molecular layer can be controlled by the deposition parameters and post-deposition annealing to obtain films ranging from amorphous to a highly aggregated state. The molecular layer has a uniaxial structure with excitonic transitions whose transition dipole moments are well defined. The presence of the molecular layer results in an enormous increase in the response of the phototransistor. We further demonstrate that the signal-enhancement is due to p-photodoping of the graphene. The spectroscopic photoresponse suggests that the photodoping via monomers and molecular aggregates takes place differently. Our photodetector is a platform to study the influence of molecular aggregation and order on charge transport processes between aggregated organic semiconductors and two-dimensional materials.
title Tunable photogating in a molecular aggregate coupled graphene phototransistor
topic Mesoscale and Nanoscale Physics
Optics
url https://arxiv.org/abs/2505.17232