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Volume 6 Research & Reviews: Journal of Material Sciences
ISSN: 2321-6212 Materials Physics 2018
August 16-17, 2018
Page 55
conferenceseries.com
August 16-17, 2018 | London, UK
4th International Conference on
Condensed Matter and Materials Physics
Samit K Ray, Res. Rev. J Mat. Sci. 2018, Volume 6
DOI: 10.4172/2321-6212-C2-016
2D/SI heterostructures for photonic devices
We shall review our recent work on 2D/3D heterostructures for several electronic and photonic devices. The device using
GO/Si on illumination shows a broadband (300 nm-1100 nm) spectral response with a characteristic peak at ~700 nm,
in agreement with the photoluminescence emission from GO. Very high photo-to-dark current ratio (>105) is observed upon
illumination of UV light. On the other hand, transition metal dichalcogenides (TMDC), an emerging class of two dimensional
materials are interesting due to the presence of a finite and direct energy gap in low dimensions, with a wide range of electronic
and optical attributes. We have demonstrated the ability to gradually tailoring the optical properties of MoS2 nanocrystals in
terms of PL response and optical absorption, making them attractive for future photonic devices. Chemical doping and plasmonic
enhanced photoresponsivity of two dimensional (2D) n-WS2/p-Si heterojunctions have also been demonstrated. A sharp band-
edge absorption of the hybrid material indicates the presence of spin–orbit coupled direct band gap transitions in WS2 layers, in
addition to a broader plasmonic peak attributed to Ag nanoparticles. Stabilized Ag-nanoparticle (~4–6 nm) embedded electron
rich n-WS2 has been used to fabricate plasmon enhanced, silicon compatible heterojunction photodetectors. The detectors
exhibited superior properties, possessing a photo-to-dark current ratio of ~103, a very high responsivity (8.0 A W−1) and an EQE
of 2000% under 10 V bias. The results provide a new paradigm for intercalant impurity-free metal nanoparticle assisted exfoliation
of n-type few-layer WS2., with the nanoparticles playing a dual role by inducing chemical doping as well as tunable plasmon
enhanced absorption.
Recent Publications
1. R KChowdhury et al. (2017) Synergistic effect of polymer encapsulated silver nanoparticle dopedWS2 sheets for plasmon
enhanced 2D/3D heterojunction photodetectors. Nanoscale. 9:15591-15597.
2. A Ghorai et al. (2017) Highly luminescent WS2 quantum dots/Zno heterojunctions for light emitting devices. ACS Appl.
Mater. Interfaces. 9:558-565.
3. S Mukherjee et al. (2017) Solution processed, hybrid 2D/3D MoS2/Si heterostructures with superior junction
characteristics. Nanotechnology. 28(135203):1-11.
4. R K Chowdhury et al. (2016) Novel silicon compatible p-WS2 2D/3D heterojunction devices exhibiting broadband
photoresponse and superior detectivity. Nanoscale. 8(27):13429-13436.
5. S Mukherjee et al. (2016) Novel Colloidal MoS2 Quantum Dot Heterojunctions on Silicon Platforms for Multifunctional
Optoelectronic Devices. Scientific Reports. 6:29016.
Biography
Samit K Ray is currently the Director of S N Bose National Centre for Basic Sciences, Kolkata on lien from Indian Institute of Technology, Kharagpur. His research interests
are in the area of semiconductor nanostructures, quantum dots, photovoltaics, nanodevices and electronic materials. He has published more than 300 research papers in
peer reviewed journals, seven book chapters and co-authored a book on “Strained Silicon Heterostructures: Materials and Devices” published by IEE, UK.
Samit K Ray
S N Bose National Centre for Basic Sciences, India