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

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 fun...

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Format:	Thesis
Language:	English
Subjects:	Biosensors Field-effect transistors Titanium dioxide
Online Access:	http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/76655/1/Page%201-24.pdf http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/76655/2/Full%20text.pdf http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/76655/3/Declaration%20Form.pdf
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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 Mohd Khairuddin, Md. Arshad, Ir. Dr. 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. Universiti Malaysia Perlis (UniMAP) Thesis en http://dspace.unimap.edu.my:80/xmlui/handle/123456789/76655 http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/76655/4/license.txt 8a4605be74aa9ea9d79846c1fba20a33 http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/76655/1/Page%201-24.pdf 5c50482cc0106b6d7284b2591fb2ce77 http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/76655/2/Full%20text.pdf 4b820413c14c4425821e5998c5e265af http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/76655/3/Declaration%20Form.pdf b7963d89e14be950fa04b50dc1958999 Universiti Malaysia Perlis (UniMAP) Biosensors Field-effect transistors Titanium dioxide Institute of Nano Electronic Engineering
institution	Universiti Malaysia Perlis
collection	UniMAP Institutional Repository
language	English
advisor	Mohd Khairuddin, Md. Arshad, Ir. Dr.
topic	Biosensors Field-effect transistors Titanium dioxide
spellingShingle	Biosensors Field-effect transistors Titanium dioxide Integration of substrate-gate couple p-type anatase TiO₂ for field-effect transistor based biosensors
description	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.
format	Thesis
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
granting_institution	Universiti Malaysia Perlis (UniMAP)
granting_department	Institute of Nano Electronic Engineering
url	http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/76655/1/Page%201-24.pdf http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/76655/2/Full%20text.pdf http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/76655/3/Declaration%20Form.pdf
_version_	1776104269633552384

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

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