Mehrdad Irannejad

High-responsivity reduced graphene oxide gel photodetectors for visible-light detection with a large detection area and an end-contact interface

Herein, the engineering and characterization of a photodetector using reduced graphene oxide gel (femtogel) as an active material are reported for the first time. The photodetector is engineered such that it contains a large detection area (interdigitated) and a femtogel–metal interface. The femtogel film is precisely placed between the interdigitated electrodes, which allows us to study the performance of the photodetector that has an end-contact interface. The femtogel width (channel) is controlled by adjusting the reactive ion etching processing time during the fabrication process. In addition, the thickness of the poly(methyl methacrylate) (PMMA) and electron-beam dose during the lithography process plays a significant role in initializing a window for etching the femtogel, which affects the channel width. In the visible range, a high responsivity has been achieved as high as 0.73 A W−1 at a low power intensity of 84 mW cm−2. Moreover, 3.4 s and 5.2 s are recorded as the time response of the photocurrent for growth and decay, respectively, in the proposed femtogel photodetector. This could open a new avenue for the fabrication of graphene-based photodetectors since placing graphene and its derivatives that are in liquid form between electrodes in a nanoscale detector is still a challenge in advanced nanofabrication.

Glasses for Photonic Integration

Inorganic glasses form the backbone of dielectric materials in optics and photonic applications. In addition to offering a range of transparency windows, intrinsic physical properties of glass materials also offer flexibility of processing for the realization of fibers, films, and shaped optical elements. Traditionally, the main role of glass has been as an optically passive material. However, a significant attribute of glass as an optical medium is to host dopants such as nanoparticles or active ions in a unique chemical environment, which can be engineered via processing, by controlling the geometry to develop active and passive photonic devices, such as laser, amplification, storage media, optical switching, frequency conversion, and sensor media.

Ultrafast light interaction with Graphene oxide aqueous solution

The effects of using ethanol as a diluting solution for ultrafast laser treated GO solutions were studied. It was found that adding 10 ml of ethanol to 1 ml rGO leads to production of smoother and thinner rGO flakes; however, the production of carbonyl and the signal due to the breathing mode of sp2 were increased.

Effects of static electricity and fabrication parameters on PVDF film properties

Degree of crystallinity and

The effects of using buffer layers on nanowire bonding and conductance properties of graphene based electronic devices

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Bowtie Nanoantenna with Single-Digit Nanometer Gap for Surface-Enhanced Raman Scattering (SERS)

β-phase fraction are important factors in determining electroactive polymers performance. In the present work, effects of intrinsic static electricity, substrate type, PVDF solution concentration and drying temperature on

A Novel Femtosecond Laser‐Assisted Method for the Synthesis of Reduced Graphene Oxide Gels and Thin Films with Tunable Properties

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