Quantum Dot-Graphene Hybrid Photodetectors

Ivan Shorubalko^a, Gabriela Borin Barin^a, Rolf Brönnimann^a, Maksym Kovalenko^a^,^b, Dmitry Dirin^a^,^b, Matthias Grotevent^a^,^b, Sergii Yakunin^a^,^b

^aEMPA - Swiss Federal Laboratories for Materials Science and Technology, Überland Strasse, 129, Dübendorf, Switzerland

^bETH Zürich, Vladimir Prelog Weg 2, 8093 Zürich, Switzerland

Materials for Sustainable Development Conference (MATSUS)
Proceedings of September Meeting 2016 (NFM16)

Berlin, Germany, 2016 September 5th - 13th

Organizers: Marin Alexe, Enrique Cánovas, Celso de Mello Donega, Ivan Infante, Thomas Kirchartz, Maksym Kovalenko, Federico Rosei, Lukas Schmidt-Mende, Laurens Siebbeles, Peter Strasser, Teodor K Todorov, Roel van de Krol and Ulrike Woggon

Poster, Matthias Grotevent, 119
Publication date: 14th June 2016

In recent years hybrid quantum dot-graphene photodetectors have been made by combining the high charge carrier mobility and two dimensionality of graphene with the high light absorption coefficient of colloidal quantum dots. In addition, charge carrier types and Fermi levels alignment can be adjusted by an externally applied electrical field similar to field effect transistors. The wavelength sensitivity of the photodetector is dependent on the bandgap of the selected quantum dot material allowing for QD-graphene hybrid photodetectors with sensitivities from UV to IR to be manufactured.^[1-3]QD-graphene photodetectors are usually fabricated on top of a Si/SiO₂ wafer. Graphene is transferred on top of the dielectric layer and electrically connected with gold electrodes. Colloidal quantum dots as the absorbing material are deposited on top of graphene. Under light illumination, with wavelength energies larger than the bandgap, excitons are generated. Typically one charge carrier type is transferred to the graphene, and the second type is trapped in the quantum dot, generating an additional external electrical field. Due to this so called “photogating effect” the conductance of graphene changes significantly under the incident light. When light is switched off, trapped charge carriers, depending on their lifetime (usually ms), leak out of quantum dots resulting in a neutral total charge in the QD layer. The operation speed of QD-graphene hybrid photodetectors is limited by rather slow recovering time. The efficiency of these hybrid detectors depends on various parameters, such as quality of graphene, quantum dot materials, and their ligands. Here we present the use of inorganically capped quantum dots (usually organically capped quantum dots were investigated) and commercially available graphene. Furthermore, fabrication of multiple pixel detector arrays instead of single pixels are investigated aiming towards applications such as in spectrometers.

[1] G. Konstantatos, M. Badioli, L. Gaudreau, J. Osmond, M. Bernechea, F. Pelayo Garcia de Arquer, F. Gatti, F. H. L. Koppens, Nat. Nanotechnol. 2012, 7, 363-368.

[2] L. Turyanska, O. Makarovsky, S. A. Svatek, P. H. Beton, C. J. Mellor, A. Patanè, L. Eaves, N. R. Thomas, M. W. Fay, A. J. Marsden, N. R. Wilson, Adv. Electron. Mater. 2015, 1, 1500062.

[3] W. Guo, S. Xu, Z. Wu, N. Wang, M. M. T. Loy, S. Du, Small 2013, 9, 3031-3036.

nanoGe is a prestigious brand of successful science conferences that are developed along the year in different areas of the world since 2009. Our worldwide conferences cover cutting-edge materials topics like perovskite solar cells, photovoltaics, optoelectronics, solar fuel conversion, surface science, catalysis and two-dimensional materials, among many others.

MATSUS

Previously nanoGe Spring Meeting (NSM) and nanoGe Fall Meeting (NFM), MATSUS is a multiple symposia conference focused on a broad set of topics of advanced materials preparation, their fundamental properties, and their applications, in fields such as renewable energy, photovoltaics, lighting, semiconductor quantum dots, 2-D materials synthesis, charge carriers dynamics, microscopy and spectroscopy semiconductors fundamentals, etc.

International Conference on Hybrid and Organic Photovoltaics

International Conference on Hybrid and Organic Photovoltaics (HOPV) is celebrated yearly in May. The main topics are the development, function and modeling of materials and devices for hybrid and organic solar cells. The field is now dominated by perovskite solar cells but also other hybrid technologies, as organic solar cells, quantum dot solar cells, and dye-sensitized solar cells and their integration into devices for photoelectrochemical solar fuel production.

Asia-Pacific International Conference on Perovskite, Organic Photovoltaics and Optoelectronics

The main topics of the Asia-Pacific International Conference on Perovskite, Organic Photovoltaics and Optoelectronics (IPEROP) are discussed every year in Asia-Pacific for gathering the recent advances in the fields of material preparation, modeling and fabrication of perovskite and hybrid and organic materials. Photovoltaic devices are analyzed from fundamental physics and materials properties to a broad set of applications. The conference also covers the developments of perovskite optoelectronics, including light-emitting diodes, lasers, optical devices, nanophotonics, nonlinear optical properties, colloidal nanostructures, photophysics and light-matter coupling.

International Conference on Perovskite Thin Film Photovoltaics Perovskite Photonics and Optoelectronics

The International Conference on Perovskite Thin Film Photovoltaics Perovskite Photonics and Optoelectronics (NIPHO) is the best place to hear the latest developments in perovskite solar cells as well as on recent advances in the fields of perovskite light-emitting diodes, lasers, optical devices, nanophotonics, nonlinear optical properties, colloidal nanostructures, photophysics and light-matter coupling.