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Joint Conference
July 17-18, 2017 Chicago, USA
International Conference on
DIAMOND AND CARBON MATERIALS & GRAPHENE AND SEMICONDUCTORS
Volume 6, Issue 6 (Suppl)
J Material Sci Eng, an open access journal
ISSN: 2169-0022
Diamond and Carbon 2017 & Graphene 2017
July 17-18, 2017
J Material Sci Eng 2017, 6:6(Suppl)
DOI: 10.4172/2169-0022-C1-077
Synthesis and characterization of graphene using PECVD and its field emission applications
Mushahid Husain
M J P Rohilkhand University, India
G
raphene is a two dimensional structure of sp2 hybridised carbon atoms arranged in a hexagonal honeycomb like pattern.
Its extraordinary and exciting electrical, optical and mechanical properties have made it a focal point of contemporary
research in material science and have earned it the status of wonder material of 21st century. Our objective is to synthesis
graphene sheets in a controlled manner in terms of number of layers and to observe for its properties like electrical conductivity,
absorbance, transmittance and field emission which could be exploited in development of modern age opto-electronic devices.
We have successfully synthesised high quality graphene on copper (Cu) coated silicon (Si) substrate at very large area using
plasma enhanced chemical vapour deposition (PECVD) method at temperature as low as 600°C. SEM and TEM images
showed the surface morphology of as grown samples is quite uniform having single layered graphene (SLG) to few layered
graphene (FLG). The G and G’ peaks of stokes phonon energy shift obtained in Raman spectroscopy confirmed that the
sample consisted of a number of SLG’s and FLG’s. The field emission characteristics of as-grown graphene samples studied
in planar diode configuration at room temperature depict that the as grown graphene is good field emitter with low turn-on
field, higher field amplification factor and long term emission current stability. Other techniques such as low pressure chemical
vapour deposition (LPCVD) and modified Hummer’s methods have also been employed for successful synthesis of graphene
and r-GO (reduced graphene oxide). The optical studies of these samples show that our samples had more than 90% optical
transparency to visible light making it useful for opto-electronic applications.
mush_phys@rediffmail.comGraphene based heterostructures used for high performance broadband photodetectors
Shaojuan Li
Soochow University, China
G
raphene has recently emerged as a potential candidate to address the shortcomings of traditional IV and III-V
semiconductors for fast and broadband photodetectors. Graphene photodetectors can convert light into electrical
signal over a broad electromagnetic spectrum from ultraviolet (UV) to terahertz (THz) range. However, the intrinsic optical
responsivity of pure graphene-based transistors is usually poor (~10-2 AW-1) due to its relatively low absorption cross-section,
fast recombination rate and the absence of gain mechanism. This has led to the formation of heterostructures of graphene
with other gain materials that have a band gap, owing to the enhanced device performance in terms of photoresponsivity and
photoconductive gain in these hybrid structures. Here, we reported novel photodetectors based on graphene-Bi
2
Te
3
, graphene-
M
0
Te
2
, and graphene-black phosphorus heterostructures and their application for broadband photodetectors. Our results
show that the graphene-Bi
2
Te
3
photodetector not only shows greatly enhanced responsivity (up to 35 AW-1 at 532 nm) and
an ultra-high photoconductive gain, but also has the capability for broadband photodetection from visible to near-infrared
(NIR) wavelengths. We also demonstrated that graphene-M
0
Te
2
hetero structure photodetector achieves a high responsivity
of ~970.82 AW-1 (at 1064 nm) and broadband photodetection (visible-1064 nm). Additionally, flexible devices based on the
graphene-M
0
Te
2
hetero structure also retains a good photodetection ability after thousands of times bending test (1.2% tensile
strain), with a high responsivity of ~60 AW-1 at 1064 nm. Finally, we show that the graphene-black phosphorus heterostructure
photodetector shows an ultrahigh responsivity of 3.3×103 AW-1, high photoconductive gain (1.13×109), ultrafast charge
transfer (41 fs), polarization dependent photocurrent response, and long term stability at telecommunication band of 1550 nm
wavelength. The high performance in NIR range demonstrated in this work paves the way for practical applications in remote
sensing, biological imaging and environmental monitoring using 2D materials.
sjli@suda.edu.cn