Muhamad Ramdzan Buyong, Farhad Larki, Muhamad Ikhmal Hakimi Zainal, Abdelaziz Yousif Ahmed Almahi, Ahmad Ghadafi Ismail, Azrul Azlan Hamzah, Aminuddin Ahmad Kayani Kayani, Céline Elie Caille and Burhanuddin Yeop Majlis
This paper aims to present the capacitance characterization of tapered dielectrophoresis (DEP) microelectrodes as micro-electro-mechanical system sensor and actuator device. The…
Abstract
Purpose
This paper aims to present the capacitance characterization of tapered dielectrophoresis (DEP) microelectrodes as micro-electro-mechanical system sensor and actuator device. The application of DEP-on-a-chip (DOC) can be used to evaluate and correlate the capacitive sensing measurement at an actual position and end station of liquid suspended targeted particles by DEP force actuator manipulation.
Design/methodology/approach
The capability of both, sensing and manipulation was analysed based on capacitance changes corresponding to the particle positioning and stationing of the targeted particles at regions of interest. The mechanisms of DEP sensor and actuator, designed in DOC applications were energized by electric field of tapered DEP microelectrodes. The actual DEP forces behaviour has been also studied via quantitative analysis of capacitance measurement value and its correlation with qualitative analysis of positioning and stationing of targeted particles.
Findings
The significance of the present work is the ability of using tapered DEP microelectrodes in a closed mode system to simultaneously sense and vary the magnitude of manipulation.
Originality/value
The integration of DOC platform for contactless electrical-driven with selective detection and rapid manipulation can provide better efficiency in in situ selective biosensors or bio-detection and rapid bio-manipulation for DOC diagnostic and prognostic devices.
Details
Keywords
Muhamad Ramdzan Buyong, Farhad Larki, Celine Elie Caille, Norazreen Abd Aziz, Ahamad Ghadafi Ismail, Azrul Azlan Hamzah and Burhanuddin Yeop Majlis
This paper aims to present the dielectrophoresis (DEP) force (FDEP), defined as microelectrofluidics mechanism capabilities in performing selective detection and rapid…
Abstract
Purpose
This paper aims to present the dielectrophoresis (DEP) force (FDEP), defined as microelectrofluidics mechanism capabilities in performing selective detection and rapid manipulation of blood components such as red blood cells (RBC) and platelets. The purpose of this investigation is to understand FDEP correlation to the variation of dynamic dielectric properties of cells under an applied voltage bias.
Design/methodology/approach
In this paper, tapered design DEP microelectrodes are used and explained. To perform the characterization and optimization by analysing the DEP polarization factor, the change in dynamic dielectric properties of blood components are observed according to the crossover frequency (fxo) and adjustment frequency (fadj) variation for selective detection and rapid manipulation.
Findings
Experimental observation of dynamic dielectric properties change shows clear correlation to DEP polarization factor when performing selective detection and rapid manipulation. These tapered DEP microelectrodes demonstrate an in situ DEP patterning efficiency more than 95%.
Research limitations/implications
The capabilities of tapered DEP microelectrode devices are introduced in this paper. However, they are not yet mature in medical research studies for various purposes such as identifying cells and bio-molecules for detection, isolation and manipulation application. This is because of biological property variations that require further DEP characterization and optimization.
Practical implications
The introduction of microelectrofluidics using DEP microelectrodes operate by selective detecting and rapid manipulating via lateral and vertical forces. This can be implemented on precision health-care development for lab-on-a-chip application in microfluidic diagnostic and prognostic devices.
Originality/value
This study introduces a new concept to understand the dynamic dielectric properties change. This is useful for rapid, label free and precise methods to conduct selective detection and rapid manipulation of mixtures of RBC and platelets. Further, potential applications that can be considered are for protein, toxin, cancer cell and bacteria detections and manipulation. Implementation of tapered DEP microelectrodes can be used based on the understanding of dynamic dielectric properties of polarization factor analysis.
Details
Keywords
Arash Dehzangi, Farhad Larki, Sawal Hamid Md Ali, Sabar Derita Hutagalung, Md Shabiul Islam, Mohd Nizar Hamidon, Susthitha Menon, Azman Jalar, Jumiah Hassan and Burhanuddin Yeop Majlis
The purpose of this paper is to analyse the operation of p-type side gate junctionless silicon transistor (SGJLT) in accumulation region through experimental measurements and 3-D…
Abstract
Purpose
The purpose of this paper is to analyse the operation of p-type side gate junctionless silicon transistor (SGJLT) in accumulation region through experimental measurements and 3-D TCAD simulation results. The variation of electric field components, carrier’s concentration and valence band edge energy towards the accumulation region is explored with the aim of finding the origin of SGJLT performance in the accumulation operational condition.
Design/methodology/approach
The device is fabricated by atomic force microscopy nanolithography on silicon-on-insulator wafer. The output and transfer characteristics of the device are obtained using 3-D Technology Computer Aided Design (TCAD) Sentaurus software and compared with experimental measurement results. The advantages of AFM nanolithography in contact mode and Silicon on Insulator (SOI) technology were implemented to fabricate a simple structure which exhibits the behaviour of field effect transistors. The device has 200-nm channel length, 100-nm gate gap and 4 μm for the distance between the source and drain contacts. The characteristics of the fabricated device were measured using an Agilent HP4156C semiconductor parameter analyzer (SPA). A 3-D TCAD Sentaurus tool is used as the simulation platform. The Boltzmann statistics is adopted because of the low doping concentration of the channel. Hydrodynamic model is taken to be as the main transport model for all simulations, and the quantum mechanical effects are ignored. A doping dependent Masetti mobility model was also included as well as an electric field dependent model with Shockley–Read–Hall (SRH) carrier recombination/generation.
Findings
We have obtained that the device is a normally on state device mainly because of the lack of work functional difference between the gate and the channel. Analysis of electric field components’ variation, carrier’s concentration and valence band edge energy reveals that increasing the negative gate voltage drives the device into accumulation region; however, it is unable to increase the drain current significantly. The positive slope of the hole quasi-Fermi level in the accumulation region presents mechanism of carriers’ movement from source to drain. The influence of electric field because of drain and gate voltage on charge distribution explains a low increasing of the drain current when the device operates in accumulation regime.
Originality/value
The proposed side gate junctionless transistors simplify the fabrication process, because of the lack of gate oxide and physical junctions, and implement the atomic force microscopy nanolithography for fabrication process. The optimized structure with lower gap between gate and channel and narrower channel would present the output characteristics near the ideal transistors for next generation of scaled-down devices in both accumulation and depletion region. The presented findings are verified through experimental measurements and simulation results.