ION-INDUCED DNA GRAPHENE FIELD EFFECT TRANSISTOR CURRENT MODULATION

Lead contamination a severe environmental problems as it is risky for human
health and the environment. Lead are toxic and harmful as they can penetrate the
human body easily through water, food, and air. Lead can cause serious health
complication even though under a low dose exposure. Therefore, numerous attempt
have been made to evolve sensors for detecting and monitoring lead ion as an initiative
for treating lead contamination. As such, various methods for lead ions removal from
water have been introduced but due to their limitations, a more effective method is
highly required. Hence, a DNA Graphene Field Effect Transistor (GFET) has been
developed in this study as another alternative for lead ion detection. In this work, the
sensor is fabricated and characterized to analyzed its sensitivity and selectivity for the
detection of lead in contaminated water sources. The graphene attached on the sensor
is synthesized using a Low-Pressure Chemical Vapor Deposition (LPCVD) and is
functionalized with the Guanine-rich DNA to enhance the sensing element of the
sensor. This project involves two main phases which are sensor fabrication and the
characterizations of the sensor. Then the sensitivity of the sensor towards the lead ions
are observed using Agilent B1500a Semiconductor Parameter Analyzer where the I-V
characteristics of the sensor are analyzed to determine its sensitivity towards lead ions.
The fabricated sensor shows typical GFET I-V characteristics with a minimum point
known as the charge neutrality point (CNP) where the shift of CNP is used as the
sensor’s response. With high sensitivity towards the lead ions, the sensor designed
which can sense the availability of lead ions under the concentration as low as 20nM
can be further developed into a portable instrument as a sensing device for lead
detection.