Joint research project

Hybrid 3D Chiral Metamaterial/2D MoS2 Phototransistors for Circularly Polarized Light Detection (HYSPID)

Project leaders
Massimo Cuscuna, Ayaz Bayramov
AZERBAIJAN - ANAS - Azerbaijan National Academy of Sciences
CNR/ANAS biennio 2018-2019 2018-2019
Physical sciences and technologies of matter
Thematic area
Physical sciences and technologies of matter
Status of the project

Research proposal

Circularly polarized light is central to many photonic technologies, including circularly polarized ellipsometry-based tomography,[1,2] optical communication of spin information,[3] quantum-based optical computing and information processing.[4,5] The development of these technologies requires the realization of miniature, integrated devices capable of detecting the chirality or handedness of circularly polarized light.
Here, we aim to develop the first circularly polarized light-detecting hybrid 3D chiral metamaterial/2D MoS2 phototransistor. It will combine helical shaped 3D nanostructures[6] able to highly select the handedness of incident circularly polarized light and a monolayer of MoS2 working as highly efficient photoresponsive semiconducting material in the visible range.[7,8] Recently, Yang et al. reported circularly polarized light-detecting transistors based on organic thin film composed by chiral semiconducting molecules[9] known as helicene.[10] The quantum efficiency of these devices was very poor (~0.1%), due to both the weak coupling of chiral organic thin films dipole moments with an external light field, and the very low charge carrier mobility of organic layers leading to a limited photoresponsivity.
To overcome such limitations, HYSPID proposes an innovative backgated hybrid field-effect phototransistor architecture consisting of 3D Pt nanohelices-based metamaterial fabricated on the active semiconducting MoS2 monolayer. Recently published papers of the Italian principal investigator (PI) from Institute of Nanotechnology of the Research National Council, CNR Nanotec (Lecce, Italy) demonstrated that fully 3D nanohelices-based metamaterials realized by the focused ion/electron beam-induced deposition (FIBID/FEBID) technologies are ideal candidates for pronounced chiral response integrated in compact devices.[6,11-13] In particular, such 3D helices enable optical multifunctionalities in the visible spectral range with giant broadband circular dichroism up to 37%,[6] about two orders of magnitude greater than the one obtained with chiral organic thin films.[9] In turn, MoS2 layers have attracted a lot of attention in recent years because of its fascinating electrical and optical properties as the electron mobility of a few hundreds of cm2(Vs)-1,[14] and the tunable band gaps depending on the number of atomic layers: bulk MoS2 has an indirect band gap of 1.2 eV, whereas a single layer has a direct band gap of 1.8 eV.[15] So far, several methods have been proposed to prepare MoS2 atomic thin layers: mechanical exfoliation is an easy and efficient method for obtaining defect-free monolayers,[14] but not suitable for the large-scale production of MoS2 films. Although the chemical vapor deposition process has made the most significant progress in the growth of high quality MoS2 layers,[16] this technique is not yet sufficiently suited for the synthesis of MoS2 single-layers on a large scale. Considered the intriguing and complex picture on this last topic, we decide to use the innovative atomic layer deposition (ALD) technique, recently installed at CNR Nanotec, for MoS2 growth. ALD is based on a self-limiting reaction and offers precise thickness control on an atomic scale and excellent thickness uniformity even on very large-area substrates enabling MoS2 to be used for reliable and innovative device development. The fully characterization of MoS2 films will be performed at the Institute of Physics of the Azerbaijan National Academy of Sciences, ANAS (Baku, Azerbaijan). The latter is a leading organization on scientific research, knowledge transfer and graduate education in physics in Azerbaijan. Involved in the HYSPID project, the PI and supporting team (two researchers, one is a young scientist under 40 years old) have an extensive experience in physical characterization techniques (Transmission Electron Microscopy, X-ray Diffraction, Raman and Ellipsometry Spectroscopies, Atomic Force Microscopy) of several innovative materials[17-19] as well as of transition metal dichalcogenides as confirmed by a work in press.[20] Such expertise will permit us to easily optimize the MoS2 monolayer deposition, representing the "hot task" of the whole proposal. The optimized monolayer will be first deposited on oxidized doped silicon wafer working as backgate; after, source and drain metal contacts will be defined at CNR Nanotec through optical lithography providing bottom gate top contact single-layer transistors. The latter represent a well-established know-how of the Italian PI.[21] The growth of 3D Pt helices on the transistor photoresponsive channel will be carried out by FIBID or FEBID technology in order to avoid any MoS2 structural damage. Finally, photocurrent measurements will be performed at ANAS evaluating the photoresponsivity to left- and right-handed circular polarized incident light. The groups involved in the HYSPID project have complementary expertise and equipments which allow to reach the project aim.
References: 1) Opt. Express 19, 5431-5441 (2011); 2) Appl. Optics 48, 758-764 (2009); 3) Appl. Phys. Lett. 98, 162508 (2011); 4) Nature 443, 557-560 (2006); 5) Nature Photon. 4, 549-552 (2010); 6) Nat. Commun. 6, 6484 (2015); 7) Adv. Mater. 25, 3456-3461 (2013), 8) Small 11, 2392-2398 (2015); 9) Nat. Photonics 7, 634 (2013); 10) Chem. Rev. 112, 1463 (2012); 11) ACS Photonics 2, 105-114 (2015); 12) Nanoscale 7, 18081 (2015) 13) Nano Lett. 16, 5823-5828 (2016); 14) Nat. Nanotechnol. 6, 147-150 (2011); 15) Phys. Rev. Lett. 105, 136805 (2010); 16) Nanoscale 7, 7802-7810 (2015); 17) Physica Status Solidi C 12, 781-784 (2015); 18) JJAP 42, 5145-5152 (2003); 19) Surface Engineering and Applied Electrochemistry 49, 359-367 (2013); 20) Applied Surface Science, in Press, Ellipsometric characterization of MoSe2 thin layers obtained by thermal treatment of molybdenum in selenium vapor; 21) Solid-State Electronics 52, 348-352 (2008).

Research goals

The proposed project is designed to strengthen research collaboration between the Institute of Physics of ANAS and Italian Research Institutes as CNR Nanotec. The project complies with the EU strategies for international cooperation by providing mobility and access to research facilities between the centers with similar research interests. Furthermore, this project will facilitate the collaboration of ANAS with the Italian Research Area in research topics covered by a thematic priority as nanotechnologies. In fact, the project aims to develop the first hybrid 3D chiral metamaterial/2D MoS2 phototransistor able to selectively detect the handedness of circularly polarized light. We will combine helical shape 3D chiral nanostructures able to efficiently select left- and right-handed circularly polarized light and a monolayer of MoS2 working as highly efficient photoresponsive material. We believe that this compact device will open up the possibility to detect circularly polarized light with a disruptive efficiency in a highly integrated photonic platform. The scientific results will be published in international journals and will boost participation in future EU calls concerning ICT.
The project ensures the compliance of ANAS and CNR Nanotec research activities with socio-economic needs of the countries and provides better career opportunities for young scientists as the Italian PI and two researchers (one for each team) under 40 years old.

Last update: 27/11/2021