Photodetectors are of great interest in several technological applications thanks to their capability to convert an optical signal into an electrical one through light-matter interactions. In particular, broadband photodetectors are used in multiple applications such as environmental monitoring, imaging, fire detection, and astronomical observations. We present a two-dimensional photodiode heterojunction based on reduced graphene oxide (rGO) deposited on an n-type Silicon substrate. We report on the electro-optical properties of the device that have been measured in dark and light conditions into a spectral range from UV to IR. The room temperature current–voltage (I–V) measurements of rGO/n-Si photodetector exhibits a reverse saturation current linearly dependent on the light power. The main figures of merit of the photodetector such as linearity and responsivity have been evaluated and compared with the recent progress obtained substituting the rGO with a graphene single layer (Gr) on the similar n-Si substrate. The photoconductive properties and analysis of the two devices are presented and discussed. Finally, the experimental results demonstrate the feasibility of the rGO/n-Si and Gr/n-Si device to detect light from UV to IR light, nominating graphene-based heterojunction as a novel candidate for the realization of new broadband photodetectors.
Nowadays, due to the competitive economic scenario, industries ever more need to focus on manufacturing speed, increasing efficiency and steady quality. More industrial sectors see additive manufacturing (AM) as a possible way to enhance their processes and increase production efficiency. Thanks to its versatility the Fused Deposition Modelling (FDM), also known as Fused Filament Fabrication (FFF) technique, is one the most attractive processes in Industry 4.0 paradigm. This technique, thanks to its low-cost, is spreading widely in industrial sectors, from biomedical to aerospace to cite some. In this frame a valid solution is to use composite materials Among many, particular attention is paid to thermoplastic systems based on polyether-ether-ketone (PEEK) reinforced with short carbon fibre (CF). The PEEK is a high-performance semi-crystalline thermoplastic polymer that belongs to the polyaryl-ether-ketone family (PAEK). 3D printing, being a novel technology, it must be validated by understanding the behaviours of components and structures. At this purpose, we used different optical techniques for analysing advanced short fibre composites realized by 3D printing. Different CFR-PEEK samples with short carbon fibre at 10% by weight were realized by the FFF technique and characterized in terms of failure mode and mechanical behaviour. Optical tools have been used to retrieve full-field data and expand information about the mechanical behaviour of the investigated material, i.e. 2D Digital Image Correlation (2D-DIC) and Electronic Speckle Pattern Interferometry (ESPI), Optical Microscopy (OM) and Scanning Electron Microscopy (SEM).
Nowadays the use of advanced composite materials in aeronautics, both civil and military, in automotive and in sport applications, citing some, is well established. The characteristics of composite materials in terms of weight, fatigue resistance and corrosion resistance make them competitive with respect to conventional ones. On the other side, the fabrication process of the most employed composites reinforced by carbon fibers or glass fibers, needs of complex steps that not always are environmental complaisant. Moreover, such fibers are not themselves “green”. For these reasons, in the last decades, the use of natural reinforcing fibers has gained an increasing attention allowing the development of new materials with the same advantages of composite systems but respecting the environment. Furthermore, such materials for their structural complexity are not always compatible with the use of standard non-destructive evaluation as the ultrasounds methods. In this work the efficiency of the employment of optical interferometric techniques as nondestructive evaluation methods in full field modality is proved on novel “green” composite materials. In particular, Electronic Speckle Pattern Interferometry has been tested on different kinds of specimens after flexural tests.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.