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Integration of substrate-gate couple p-type anatase TiO₂ for field-effect transistor based biosensors

Master of Science in Nano electronic Engineering

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Bibliographic Details
Main Author: Adzhri, Rahmat
Other Authors: Mohd Khairuddin, Md. Arshad, Ir. Dr.
Format: Thesis
Language:English
Published: Universiti Malaysia Perlis (UniMAP) 2017
Subjects:
Biosensors
Field-effect transistors
Titanium dioxide
Online Access:http://dspace.unimap.edu.my:80/xmlui/handle/123456789/76655
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spelling my.unimap-766552022-11-01T01:22:47Z Integration of substrate-gate couple p-type anatase TiO₂ for field-effect transistor based biosensors Adzhri, Rahmat Mohd Khairuddin, Md. Arshad, Ir. Dr. Biosensors Field-effect transistors Titanium dioxide Master of Science in Nano electronic Engineering The term “biosensor” is a short form for “biological sensor”. A biosensor is generally defined as an analytical device, which converts the biochemical responses into quantifiable electronic signal. The device is made up of a transducer and biological receptor. The transducer surface needs to be functionalized with biological receptors such as an antibody, an enzyme or a nucleic acid. The biological receptor is employed to identify the specific target (i.e. DNA or antigen) molecule and the transducer to transform the specific interaction of the biomolecule into electronic signal. This method allows high sensitivity, rapid response and label-free detection. In this work, the integration of substrate-gate coupling of field-effect transistor (FET) based sensor with p-type anatase TiO₂ as a transducer material for detection of cardiac troponin I biomarker is presented. The work is initiated with fabrication of substrate-gated FET based biosensor on p-type silicon-on-insulator (SOI) wafer. Photolithography process with three different masks are used; 1) to create 10 μm channel in between the source and drain area, 2) to expose substrate-gate electrode through the top-silicon and buried oxide (SiO₂) layer, and 3) Al metal contact deposition for source, drain and substrate gate electrodes. Next, TiO₂ that acts as a transducer material is deposited on top of the channel by using sol-gel technique, creating a thin film TiO₂ on the surface. Several characterization methods have been used to determine the TiO₂ properties such as surface morphology (AFM, SEM), material crystallinity (XRD), surface functionalization (FTIR, XPS), and electrical characteristics (SPA). The deposited TiO₂ thin film possess p-type anatase structure due to titanium vacant defect, with average grain size of 65 nm. The fabricated device with TiO₂ thin film (before functionalization and detection of biomolecule), shows that there is electrical flow with the presence of TiO₂ connecting between source and drain, and it can be modulated with substrate-gate bias. Subsequently, the TiO₂ surface is functionalized with APTES and Glutaraldehyde prior to be subjected into antibody-antigen interaction, characterized by using XPS and FTIR. It shows, the changes or the presence of peaks at each surface functionalization proved that the chemical bonding have occurred. To demonstrate the functionality and performance of for biomolecule detection, the device is demonstrated to detection of cardiac troponin biomarker (cTnI) with concentration from 1ng/ml until 10 μg/ml. cTnI is a gold standard for diagnosis of cardiovascular disease. With the presence of substrate-gate biasing (Vbg = - 3 V), the device demonstrated significant amplification signal with LOD of 0.238 ng/ml can be achieved. This bring to a confirmation that the p-type anatase TiO2 offers excellent interaction with cTnI biomolecule. Coupled with substrate-gated FET, enhance sensitivity of bio-sensing can be achieved due modulation of electrical conductivity along the channel. 2017 2022-11-01T01:22:47Z 2022-11-01T01:22:47Z Thesis http://dspace.unimap.edu.my:80/xmlui/handle/123456789/76655 en Universiti Malaysia Perlis (UniMAP) Universiti Malaysia Perlis (UniMAP) Institute of Nano Electronic Engineering
institution Universiti Malaysia Perlis
building UniMAP Library
collection Institutional Repository
continent Asia
country Malaysia
content_provider Universiti Malaysia Perlis
content_source UniMAP Library Digital Repository
url_provider http://dspace.unimap.edu.my/
language English
topic Biosensors
Field-effect transistors
Titanium dioxide
spellingShingle Biosensors
Field-effect transistors
Titanium dioxide
Adzhri, Rahmat
Integration of substrate-gate couple p-type anatase TiO₂ for field-effect transistor based biosensors
description Master of Science in Nano electronic Engineering
author2 Mohd Khairuddin, Md. Arshad, Ir. Dr.
author_facet Mohd Khairuddin, Md. Arshad, Ir. Dr.
Adzhri, Rahmat
format Thesis
author Adzhri, Rahmat
author_sort Adzhri, Rahmat
title Integration of substrate-gate couple p-type anatase TiO₂ for field-effect transistor based biosensors
title_short Integration of substrate-gate couple p-type anatase TiO₂ for field-effect transistor based biosensors
title_full Integration of substrate-gate couple p-type anatase TiO₂ for field-effect transistor based biosensors
title_fullStr Integration of substrate-gate couple p-type anatase TiO₂ for field-effect transistor based biosensors
title_full_unstemmed Integration of substrate-gate couple p-type anatase TiO₂ for field-effect transistor based biosensors
title_sort integration of substrate-gate couple p-type anatase tio₂ for field-effect transistor based biosensors
publisher Universiti Malaysia Perlis (UniMAP)
publishDate 2017
url http://dspace.unimap.edu.my:80/xmlui/handle/123456789/76655
_version_ 1751537955678191616
score 13.214268

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