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Article
Publication date: 2 May 2017

Sharipah Nadzirah and Uda Hashim

The purpose of this study is to fabricate a transducer-based TiO2 interdigitated microelectrodes with various gap sizes. The most stable electrical properties have been…

Abstract

Purpose

The purpose of this study is to fabricate a transducer-based TiO2 interdigitated microelectrodes with various gap sizes. The most stable electrical properties have been selected for Escherichia. coli O157:H7 DNA detection.

Design/methodology/approach

Sol-gel was used to synthesize TiO2 nanoparticles. Lift-off photolithography process was used for fabrication of interdigitated electrodes (IDEs) and dry-state DNA detection was done using a Picoammeter.

Findings

TiO2 nanoparticles IDEs with 16-um gap size is able to detect DNA of E. coli in a dry state.

Originality/value

This paper describes IDEs for dry-state detection of E. coli O157:H7 DNA. The technique presented in this paper ensures the high uniformity of nanoparticle deposition on the finger electrode.

Details

Microelectronics International, vol. 34 no. 2
Type: Research Article
ISSN: 1356-5362

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Article
Publication date: 20 June 2016

Yijun Teh, Asral Bahari Jambek and Uda Hashim

This paper aims to discuss a nanoscale biosensor and its signal analysis algorithms.

Abstract

Purpose

This paper aims to discuss a nanoscale biosensor and its signal analysis algorithms.

Design/methodology/approach

In this work, five nanoscale biosensors are reviewed, namely, silicon nanowire field-effect-transistor biosensors, polysilicon nanogap capacitive biosensors, nanotube amperometric biosensors, gold nanoparticle-based electrochemical biosensors and quantum dot-based electrochemical biosensors.

Findings

Each biosensor produces a different output signal depending on its electrical characteristics. Five signal analysers are studied, with most of the existing signal analyser analyses based on the amplitude of the signal. Based on the analysis, auto-threshold peak detection is proposed for further work.

Originality/value

Suitability of the signal processing algorithm to be applied to nano-biosensors was reported.

Details

Sensor Review, vol. 36 no. 3
Type: Research Article
ISSN: 0260-2288

Keywords

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Article
Publication date: 26 July 2013

Muhammad Kashif and Uda Hashim

The purpose of the current research is to use impedance spectroscopy to study the AC parameters that varied with frequency such as impedance, dielectric constant and…

Abstract

Purpose

The purpose of the current research is to use impedance spectroscopy to study the AC parameters that varied with frequency such as impedance, dielectric constant and conductivity of ZnO nanorods MSM structure in the range of 1 Hz to 10 MHz under atmospheric conditions.

Design/methodology/approach

ZnO nanorods were grown on glass substrate using low cost sol‐gel method. 0.35 M seed solution was prepared by dissolving zinc acetate dihydrate in 2‐methoxyethanol and monoethanolamine which acts as a stabilizer was added drop‐wise. Prior to the deposition, glass slide was cut into pieces of 1.5 cm×2 cm. Ultra‐sonication process is used to clean the glass substrate using acetone, ethanol, and de‐ionized (DI) water for 5 min. The prepared seed solution was coated on glass substrate using spin coater at spinning speed of 3000 rpm for 30 s and then dried at 250°C for 10 min followed by annealing at 550°C for 2 h. The hydrothermal growth was carried out in aqueous solution of zinc nitrate hexahydrate (25 mM), hexamethyltetramine (25 mM).

Findings

ZnO nanorods were characterized using scanning electron microscope (SEM), X‐ray diffraction (XRD) and impedance spectroscopy. The real part of impedance (Z′) showed two semicircles that correspond to the distribution of the grain boundaries and electrode process. SEM image showed the densely packed ZnO nanorods on the surface of glass substrate, whereas XRD revealed the grown nanorods have c‐axis orientation. The results show that the impedance dielectric increases as the frequency decreases while the conductivity showed the opposite behavior.

Originality/value

This paper demonstrates the electron transport mechanism of ZnO nanorods at room temperature to understand the frequency dependent parameters.

Details

Microelectronics International, vol. 30 no. 3
Type: Research Article
ISSN: 1356-5362

Keywords

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Article
Publication date: 27 July 2012

Muhammad Kashif, Uda Hashim, Eaqub Ali, Ala'eddin A. Saif, Syed Muhammad Usman Ali and Magnus Willander

The purpose of this paper is to investigate the electrical transport mechanism of the Al‐doped ZnO nanorods at different temperatures by employing impedance spectroscopy.

Abstract

Purpose

The purpose of this paper is to investigate the electrical transport mechanism of the Al‐doped ZnO nanorods at different temperatures by employing impedance spectroscopy.

Design/methodology/approach

Al‐doped ZnO nanorods were grown on silicon substrate using step sol‐gel method. For the seed solution preparation Zinc acetate dihydrate, 2‐methoxyethanol, monoethanolamine and aluminum nitrite nano‐hydrate were used as a solute, solvent, stabilizer and dopant, respectively. Prior to the deposition, P‐type Si (100) wafer was cut into pieces of 1 cm×2 cm. The samples were then cleaned in an ultrasonic bath with acetone, ethanol, and de‐ionized (DI) water for 5 min. The prepared seed solution was coated on silicon substrate using spin coater at spinning speed of 3000 rpm for 30 s and then dried at 250°C for 10 min followed by annealing at 550°C for 1 h. The hydrothermal growth was carried out in a solution of zinc nitrate hexahydrate (0.025M), Hexamethyltetramine (0.025M) in DI water.

Findings

Al‐doped ZnO nanorods were characterized using scanning electron microscope (SEM), X‐ray diffraction (XRD) and impedance spectroscopy. The impedance measurements were carried out at various temperatures (100°C‐325°C). The impedance results showed that temperature has great influence on the impedance; the impedance value decreased as the temperature increased. This decrement is attributed to the increase of the mobility of the defects, especially the oxygen vacancies. The surface morphology of the samples was measured by SEM and X‐ray diffraction. The SEM images show that the high density of Al‐doped ZnO nanorods covers the silicon substrate, whereas the XRD pattern shows the (002) crystal orientation.

Originality/value

This paper demonstrates the electron transport mechanism of Al‐doped ZnO nanorods, at different temperatures, to understand the charge transport model.

Details

Microelectronics International, vol. 29 no. 3
Type: Research Article
ISSN: 1356-5362

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Article
Publication date: 29 April 2014

Qazi Humayun, Muhammad Kashif and Uda Hashim

– The purpose of this study was to investigate the performance of a single-bridge ZnO nanorod as a photodetector.

Abstract

Purpose

The purpose of this study was to investigate the performance of a single-bridge ZnO nanorod as a photodetector.

Design/methodology/approach

The fabrication of the design sensor with ∼6-μm gap Schottky contacts and bridging of the ZnO nanorod were based on conventional photolithography and wet-etching technique. Prior to bridging, the ZnO nanorods were grown by the hydrothermal process. The 0.35 M seed solution was prepared by dissolving zinc acetate dihydrate in 2-methoxyethanol, and monoethanolamine, which acts as a stabilizer, was added drop-wise. Before starting the solution deposition, and oxide, titanium (Ti) and gold (Au) layer deposition, p-type (100) silicon substrate was cleaned with Radio Corporation of America (RCA1) and RCA2, followed by dipping in diluted hydrofluoric acid. The aged solution was dropped onto the surface of the Au microgap structure, using a spin coater at a spinning speed of 3,000 rpm for 45 seconds, and then dried at 300°C for 15 minutes, followed by annealing at 400°C for 1 hour. The hydrothermal growth was carried out in an aqueous solution of zinc nitrate hexahydrate (0.025 M) and hexamethyltetramine (0.025 M).

Findings

In this study, ZnO nanorods were grown on a SiO2 substrate by the hydrothermal method. Microgap electrodes with ∼6-μm spacing were achieved by using the wet-etching process. After the growth process, an area-selective mask was utilized to reduce the number of rods between the nearby gap areas. The obtained single ZnO nanorod was tested for the UV-sensing application. The single ZnO nanorod photodetector exhibited a UV photoresponse, thereby indicating potential as a cost-effective UV detector. The response and recovery times of the fabricated device were 65 and 95 seconds, respectively. Structural analysis was captured using X-ray Diffraction (XRD), whereas surface morphology was determined using scanning electron microscopy.

Originality/value

This paper demonstrates the effect of UV photon on a single-bridge ZnO nanorod between microgap electrodes.

Details

Microelectronics International, vol. 31 no. 2
Type: Research Article
ISSN: 1356-5362

Keywords

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Article
Publication date: 26 July 2013

Chong Leong Gan, Francis Classe and Uda Hashim

The purpose of this paper is to provide a systematic method to perform long‐term reliability assessment of gold (Au) and copper (Cu) ball bonds in fineline ball grid array…

Abstract

Purpose

The purpose of this paper is to provide a systematic method to perform long‐term reliability assessment of gold (Au) and copper (Cu) ball bonds in fineline ball grid array package. Also with the aim to study the apparent activation energies (Eaa) and its associated wearout mechanisms of both Au and Cu wire in semiconductor device packaging. This paper discusses the influence of wire type on the long‐term reliability and mechanical performance after several component reliability stress tests.

Design/methodology/approach

A fineline ball grid array (FBGA) package with Cu and Au wire bonds was assembled with green molding compound and substrate. Samples are subjected for long‐term high temperature storage bake test at elevated temperatures of 150°C, 175°C and 200°C. Long‐term reliability plots (lognormal plots) are established and Eaa of both ball bonds are determined from Arrhenius plots. Detailed failure analysis has been conducted on failed sample and HTSL failure mechanisms have been proposed.

Findings

Reliability results show Au ball bond in FBGA package is observed with higher hour‐to‐failure compared to Cu ball bonds. The Eaa value of high temperature storage life (HTSL) reliability for Au ball bond is lower than Cu ball bond. Typical HTSL failure mechanism of Au ball bond is induced by micro‐voiding and AuAl intermetallic compound (IMC) micro‐cracks while CuAl IMC micro‐cracking (induced by Cl corrosion attack and micro‐cracking) caused wearout opens in Cu ball bond. These test results affirm the test‐to‐failure data collected is a useful method for lifetime prediction and Eaa calculation.

Practical implications

The paper reveals higher reliability performance of Cu ball bond in FBGA flash memory package which can be deployed in flash memory FBGA packaging with optimised package bill of materials.

Originality/value

The test‐to‐failure methodology is a useful technique for wearout reliability prediction and Eaa calculation.

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Article
Publication date: 2 August 2011

Uda Hashim, Nazwa Taib, Thikra S. Dhahi and Azizullah Saifullah

Nanobiosensors based on nanogap capacitor are widely used for measuring dielectric properties of DNA, protein and biomolecule. The purpose of this paper is to report on…

Abstract

Purpose

Nanobiosensors based on nanogap capacitor are widely used for measuring dielectric properties of DNA, protein and biomolecule. The purpose of this paper is to report on the fabrication and characterization polysilicon nanogap patterning using novelties technique.

Design/methodology/approach

Overall, the polysilicon nanogap pattern was fabricated based on conventional lithographic techniques. For size expansion technique, by employing simple dry thermal oxidation, the couple of nanogap pattern has been expanded to lowest nanogap value. The progress of nanogap pattern expansion was verified by using scanning electron microscopy (SEM). Conductivity, resistivity, and capacitance test were performed to characterize and to measure electrical behavior of full device fabrication.

Findings

SEM characterization emphasis on the expansion of polysilicon nanogap pattern increasing with respect to oxidation time. Electrical characterization shows that nanogap enhanced the sensitivity of the device at the value of nano ampere of current.

Originality/value

These simple least‐cost method does not require complicated nanolithography method of fabrication but still possible to serve as biomolecular junction. This approach can be applied extensively to different design of nanogap structure down to several nanometer levels of dimensions. A method of preparing a nanogap electrode according to the present innovation has an advantage of providing active surface that can be easily modified for immobilizations of biomolecules.

Details

Microelectronics International, vol. 28 no. 3
Type: Research Article
ISSN: 1356-5362

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Article
Publication date: 29 April 2014

Chong Leong Gan, Francis Classe, Bak Lee Chan and Uda Hashim

The purpose of this paper is to provide a systematic review on technical findings and discuss the feasibility and future of gold (Au) wirebonding in microelectronics…

Abstract

Purpose

The purpose of this paper is to provide a systematic review on technical findings and discuss the feasibility and future of gold (Au) wirebonding in microelectronics packaging. It also aims to study and compare the cost, quality and wear-out reliability performance of Au wirebonding with respect to other wire alloys such as copper (Cu) and silver (Ag) wirebonding. This paper discusses the influence of wire type on the long-term reliability tests.

Design/methodology/approach

Literature reviews are conducted based on cost and wire selections of Au, Cu or Ag wirebonding. Detailed wear-out failure findings and wire selection with cost considerations are presented in this review paper. The future and the status of Au wirebonding in microelectronics packaging are discussed in this paper.

Findings

This paper briefly reviews selected aspects of the Au ball and other alternative bonding options, focusing on reliability performance, and discusses the future of Au wirebonding in the near future in semiconductor packaging.

Practical implications

The paper reveals the technical considerations when choosing the wire types for future microelectronics packaging.

Originality/value

The in-depth technical review and strategies of the selection of wire types (Au, Cu or the latest Ag alloy) in microelectronics packaging are discussed in this paper based on previous literature studies.

Details

Microelectronics International, vol. 31 no. 2
Type: Research Article
ISSN: 1356-5362

Keywords

Content available
Article
Publication date: 12 October 2018

Anwar Allah Pitchay, Mohamed Asmy Mohd Thas Thaker, Al Amin Mydin, Zubir Azhar and Abdul Rais Abdul Latiff

Waqf (Islamic endowment) in the form of cash is important to address the problem of developing idle waqf lands. Although there are various existing models of cash waqf

Abstract

Purpose

Waqf (Islamic endowment) in the form of cash is important to address the problem of developing idle waqf lands. Although there are various existing models of cash waqf, there is still a need for innovative cash waqf models. This paper aims to offer an alternative mode of financing for developing idle waqf lands using the concepts of cooperatives and waqf.

Design/methodology/approach

The present study first evaluates relevant literature on financing issues faced by waqf institutions in developing idle waqf lands as well as existing models of cash waqf. Based on the prevailing gap in cash waqf models, the study proposes a hybrid model of cooperative-waqf to finance idle waqf lands in Malaysia.

Findings

The proposed model is unique owing to the new dimension of membership being embedded into the waqf project. It considers donors as members of the waqf project, which is funded through the cash waqf collected, and thus, donors are given the privilege to receive benefits from the commercialised projects that are developed on the waqf lands. The existing models of cash waqf use traditional methods in which donors merely contribute cash waqf without any awareness of how the contributions are utilised. Usually, this problem occurs due to the lack of reciprocal communication between cash waqf donors and waqf institutions.

Research limitations/implications

The present study examines the case of waqf land development in the context of Malaysia only. Secondly, the paper does not contain any empirical analysis, and the development of the paper is based on existing literature that discusses various models of cash waqf practised in Muslim-majority and -minority countries. Future research can conduct surveys of donors and other stakeholders on the practicality of the model.

Practical implications

It is expected that the proposed cooperative-waqf model will be able to create a synchronised relationship between cash waqf donors and waqf institutions and hence boost participation in developing waqf lands.

Originality/value

The present study adds to the existing literature in the area of waqf and cash waqf models, especially the application of this instrument in the context of Malaysia. It also offers a new hybrid model to the State Islamic Religious Councils (SIRCs) – Malaysia’s sole trustee of waqf assets management – such that the implementation of the proposed model could boost the collection of cash waqf in developing commercial projects on idle waqf lands.

Details

ISRA International Journal of Islamic Finance, vol. 10 no. 2
Type: Research Article
ISSN: 0128-1976

Keywords

Content available
Article
Publication date: 18 May 2020

Md Nahin Hossain, Md. Shamim Talukder, Abul Khayer and Yukun Bao

In the era of m-learning environments, multiple factors have been considered to explain adult learners' continuance usage intention, but largely without considering the…

Abstract

Purpose

In the era of m-learning environments, multiple factors have been considered to explain adult learners' continuance usage intention, but largely without considering the role of specific configurations of variables and how they may affect learners' intention. The purpose of this study is to show how cognitive need, subjective norms, perceived usefulness, satisfaction, confirmation, attitude and perceived ease of use combine to predict learners' frequent use intentions.

Design/methodology/approach

It is empirically validated through configurational analysis, using fuzzy-set qualitative comparative analysis (fsQCA) on 211 adult learners with experience in using Mobile learning applications (MLA).

Findings

The findings show learners' satisfaction of MLA usage combined with the cognitive need and attitude were found to be core conditions reinforcing learners' continuance intention.

Research limitations/implications

This study was conducted in the context of adult learners MLA whereby the motivations for continued usage and the nature of technological innovation could differ. In this regard, findings from this study may not be generalizable to other technological contexts.

Practical implications

In the planning and development of learning apps, software developers should pay attention to practical functions and extend key features that are frequently required for solving a problem using the new skill. On the marketing side, MLA companies should emphasize the full functionality of their apps to cater efficiently to the different needs and expectations of the learners.

Originality/value

This study contributes by extending existing knowledge on how cognitive need, satisfaction and attitude combine to increase or mitigate continuance intention to use toward the development of new configurational theories. This study fills the gap in the literature by introducing adult learners' continuance intention to use MLA and introducing through a methodological approach of fsQCA in adult learners' context.

Details

Journal of Research in Innovative Teaching & Learning, vol. 14 no. 2
Type: Research Article
ISSN: 2397-7604

Keywords

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