Candidate
Dawood Alsaedi
Title
Graphene oxide femtogel photodetector
Supervisors
Mustafa Yavuz (Mechanical & Mechatronics) and Omar Ramahi
Abstract
Even though graphene-based photodetectors show a remarkable responsivity over a wide range of wavelengths, operating a photodetector under ambient environment affects its stability and responsivity. The photodetector instability is a result of the interaction between the sensing material of the photodetector and the ambient molecules. Therefore, using a novel sensing material with minimum interaction with ambient environment results in a significant enhancement in the stability and responsivity of the photodetector.
Herein, we report a considerable enhancement in stability and responsivity of a interdigitated photodetector structure by using a novel hybrid sensing material based on the graphene derivatives and poly (methyl methacrylate), PMMA. In this work, reduced graphene oxide gel (femtogel) was used as the sensing materials by placing between the detector fingers. A remarkable improvement was observed in the responsivity and stability of the photodetector by covering the femtogel surface by a thin layer of PMMA which is transparent to the incoming light without any detrimental effect on the electrical properties of the femtogel interdigitated photodetector even after several measurements. The photoresponse in the fabricated femtogel photodetector that has ambient-exposed sensing area was dominated by a bolometric effect. However, the photovoltaic effect, high sensitivity, and stable operation were recorded in PMMA-femtogel hybrid interdigitated photodetector (PFHIP). This study open a new avenue in photodetector engineering technology that operates in an open ambient with high stability and high responsivity.