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1 – 10 of over 1000L.S. Chuah, Z. Hassan and H. Abu Hassan
This paper aims to report on the use of radio frequency nitrogen plasma‐assisted molecular beam epitaxy (RF‐MBE) to grow high‐quality n‐type In0.47Ga0.53N/GaN on Si(111) substrate…
Abstract
Purpose
This paper aims to report on the use of radio frequency nitrogen plasma‐assisted molecular beam epitaxy (RF‐MBE) to grow high‐quality n‐type In0.47Ga0.53N/GaN on Si(111) substrate using AlN as a buffer layer.
Design/methodology/approach
Structural analyses of the InGaN films were performed by using X‐ray diffraction, atomic force microscopy, and Hall measurement. Metal‐semiconductor‐metal (MSM) photodiode was fabricated on the In0.47Ga0.53N/Si(111) films. Electrical analysis of the MSM photodiodes was carried out by using current‐voltage (I‐V) measurements. Ideality factors and Schottky barrier heights for Ni/In0.47Ga0.53N, was deduced to be 1.01 and 0.60 eV, respectively.
Findings
The In0.47Ga0.53N MSM photodiode shows a sharp cut‐off wavelength at 840 nm. A maximum responsivity of 0.28 A/W was achieved at 839 nm. The detector shows a little decrease in responsivity from 840 to 200 nm. The responsivity of the MSM drops by nearly two orders of magnitude across the cut‐off wavelength.
Originality/value
Focuses on III‐nitride semiconductors, which are of interest for applications in high temperature/power electronic devices.
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L.S. Chuah, Z. Hassan and H. Abu Hassan
The purpose of this paper is to propose a new structure of GaN based metal‐semiconductor‐metal (MSM) photodiode, in which a thin unintentionally doped n‐type AlGaN layer is added…
Abstract
Purpose
The purpose of this paper is to propose a new structure of GaN based metal‐semiconductor‐metal (MSM) photodiode, in which a thin unintentionally doped n‐type AlGaN layer is added on the conventional GaN on Si(111) device structure.
Design/methodology/approach
A thin Al0.50Ga0.50N cap layer of 100 nm was incorporated in GaN MSM photodiode to enhance the effective Schottky barrier height and reduce the dark current. When the incident light with photon energy higher than the band edge of GaN but lower than the bandgap of AlGaN illuminates the front face of photodiode, the light can be transparent in the top AlGaN layer and is only absorbed by the GaN layer. As a result, the photogenerated carriers in the GaN layer would be influenced by the interface states of AlGaN/GaN. It is known that the density of the interface states is normally lower than that of surface states, so the recombination of photogenerated electron‐hole pairs will be reduced. A barrier height of 0.54 eV for normal GaN MSM photodiode was increased to the effective barrier height of 0.60 eV.
Findings
The resulting MSM photodiode shows a dark current of as low as 8.0×10−4 A at 5 V bias, which is about two orders of magnitude lower than that of normal GaN (1.0×10−2 A at 5 V bias) MSM photodiode.
Originality/value
The paper reports on barrier enhanced GaN Schottky MSM photodiode using a thin AlGaN cap layer. AlGaN cap layers were found to effectively suppress the leakage current of the GaN Schottky MSM photodiode, resulting in improved device characteristics. The dark current for the Schottky contact with the AlGaN cap layer was shown to be about about two orders of magnitude smaller than that of conventional GaN Schottky MSM photodiode.
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M.A. Abid, H. Abu Hassan, Z. Hassan, S.S. Ng, S.K. Mohd Bakhori and N.H. Abd Raof
The purpose of this paper is to study the structural and optical characterization of Alx Iny Ga1−x−y N quaternary epilayers, which were grown on c‐plane (0001) sapphire substrates…
Abstract
Purpose
The purpose of this paper is to study the structural and optical characterization of Alx Iny Ga1−x−y N quaternary epilayers, which were grown on c‐plane (0001) sapphire substrates with AlN as buffer layers using plasma assisted molecular beam epitaxy technique with indium (In) mole fraction y ranging from 0.0 to 0.1 and constant aluminum (Al) mole fraction x=0.06.
Design/methodology/approach
High‐resolution X‐ray diffraction rocking curve (HRXRD‐RC), scanning electron microscopy (SEM), energy dispersive X‐ray spectrometry (EDX), and photoluminescence (PL) spectroscopy have been measured on quaternary Alx Iny Ga1−x−y N thin films at room temperature.
Findings
HRXRD‐RC measurements confirmed that the Alx Iny Ga1−x−y N alloys had wurtzite structure. SEM images, element composition analysis by EDX, provided the evidence to show the existence of defects inside the samples contaminated by silicon from previous growth leading to nonuniformity of the epilayers, which caused decreased in the quality of the samples. PL spectra show reducing of the integrated intensity and an increasing red shift with increasing in content with reference to the ternary sample Al0.06Ga0.94N. The existence of a large amount of nonradiative recombination centers are responsible for the reduced the luminescence and the red shift provided evidence to an increase in composition inside the Alx Iny Ga1−x−y N quaternary alloys. Photoluminescence is used to determine the behavior of the near band edge emission represent the energy band gap of the quaternary films. The energy band gap decreases with increasing In composition from 0.01 to 0.1 mole fraction. This trend is expected since the incorporation of in reduced the energy band gap of ternary Al0.06Ga0.94N (3.529 eV). We have also investigated the bowing parameter of the variation of energy band gaps and found it to be very sensitive on in composition. A value of b=10.95 have been obtain for our quaternary Alx Iny Ga1−x−y N alloys.
Originality/value
This study on quaternary samples described in this paper, clearly indicates that the present of defects due to impurity contaminations has a dominant role in determining the structural and optical properties of Alx Iny Ga1−x−y N quaternary alloys.
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L.S. Chuah, Z. Hassan, H. Abu Hassan, C.W. Chin, S.M. Thahab and S.C. Teoh
The purpose of this paper is to present the characteristics of novel silicon Schottky barrier (SB) photodiodes (PDs) with aluminium nitride (AlN) (100 nm) nucleation layer.
Abstract
Purpose
The purpose of this paper is to present the characteristics of novel silicon Schottky barrier (SB) photodiodes (PDs) with aluminium nitride (AlN) (100 nm) nucleation layer.
Design/methodology/approach
Comparison was made with conventional silicon SB PDs.
Findings
It was found that smaller dark current could be achieved with AlN nucleation layer. It was also found that effective SB height increased from 0.65 to 0.71 eV with the insertion of the AlN layer. The dark leakage current for the Schottky PDs with the AlN layer was shown to be about two orders of magnitude smaller than that for the conventional silicon SB PDs.
Research limitations/implications
It is possible that the detrimental effect of interface states situated near the metal semiconductor interface was less pronounced for the sample owing to the insertion of the AlN nucleation layer.
Originality/value
There is believed to be no other report on silicon SB PDs capped with an AlN layer in the literature. This paper describes the fabricated silicon SB PDs and reports on the electrical characteristics of the devices with an AlN nucleation layer grown at low temperature.
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Abiodun Olatunji Abisuga, Cynthia Changxin Wang and Riza Yosia Sunindijo
This study aims to explore the various approaches used in the general customer service industry to develop a conceptual framework for evaluating the responses of facility managers…
Abstract
Purpose
This study aims to explore the various approaches used in the general customer service industry to develop a conceptual framework for evaluating the responses of facility managers to user post-occupancy feedback.
Design/methodology/approach
This study uses conceptual analysis based on a comprehensive review of relevant literature.
Findings
The results of the study established 24 propositions which are categorised under organisational response dimensions specific to facilities management (FM): timeliness, facilitation, redress, apology, credibility of explanation, attentiveness, effort and their relationships with overall satisfaction and post-feedback behaviour, such as word of mouth and acceptance to continue using the facilities.
Research limitations/implications
The established propositions are derived from existing theories using a deductive approach. The framework can be further enhanced to suit various applications in FM services.
Practical implications
This conceptual framework is a generic model, appropriate to many FM scenarios. The framework can be used to develop standard policies and procedures to foster and encourage collaborative relationships between users and facility managers. It reinforces transparency and trust between facility managers and users during the operation and management of the facilities, and improves FM effectiveness, facility performance and user post-occupancy experience.
Originality/value
In the FM area, no systematic approach has been previously established to evaluate and improve the response process to the users’ feedback. The proposed framework is a pioneer contribution in this area.
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L.S. Chuah, Z. Hassan, S.S. Tneh, M.A. Ahmad, S.K. Mohd Bakhori and Y. Yusof
The purpose of this paper is to propose a simple physical evaporation route in which catalyst‐free zinc oxide (ZnO) nanoscrewdrivers were deposited on silicon (Si) (111…
Abstract
Purpose
The purpose of this paper is to propose a simple physical evaporation route in which catalyst‐free zinc oxide (ZnO) nanoscrewdrivers were deposited on silicon (Si) (111) substrates.
Design/methodology/approach
Prior to the deposition, the Si (111) wafer was cut into pieces of 2×2 cm2. Then, the wafers were dipped for 1 min into mixture buffered oxide etchant to remove native oxide. Then, the samples were rinsed in an ultrasonic bath cleaned with boiling acetone, ethanol, and de‐ionized (DI) water for 10 min. Lastly, the wafers were rinsed in 25 ml DI water in stirred and then were blown dry with nitrogen. In this technique, the starting material is high‐purity metallic zinc (Zn) powder (99.99 per cent pure). Following, the Zn films were then annealed under air environment in the furnace at 500°C for 1 h deprived of any catalysts.
Findings
These ZnO samples were studied by scanning electron microscopy, high‐resolution X‐ray diffraction (HR‐XRD), and photoluminescence (PL) spectroscopy. Atomic force microscope (AFM) images were applied to ascertain surface morphology of produced ZnO nanoscrewdrivers. XRD pattern confirmed that the ZnO nanoscrewdrivers were of polycrystalline structure in universe with a hexagonal close packed type and c‐axis is perpendicular to the substrate. The peak at 34° correspond to the reflection planes of ZnO(002) crystallographic plane is perceived. The AFM surface images disclosed that the surfaces of produced ZnO thin films are not smooth. The PL spectrum of as‐synthesized nanoscrewdrivers shows a UV emission peak at 380 nm and a broad green emission peak at 500 nm.
Originality/value
The paper reports on a simple physical evaporation route, ZnO nanoscrewdrivers were synthesized via the thermal evaporation of the high‐purity Zn powders and annealed at 500°C under air atmosphere without introducing any hetero‐metal catalysts or other carrier gases approach.
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Asmiet Ramizy, Khalid Omar and Z. Hassan
The purpose of this paper is to synthesize Si (porous silicon (PS)) by laser‐induced etching (LIE) technique. The LIE process has the added advantage of a controlling size and…
Abstract
Purpose
The purpose of this paper is to synthesize Si (porous silicon (PS)) by laser‐induced etching (LIE) technique. The LIE process has the added advantage of a controlling size and optical properties without using of electrodes. The LIE process is a promising technique for fabricating many optoelectronic devices including: light‐emitting devices, detectors, sensors and large‐scale integrated circuits.
Design/methodology/approach
PS has been fabricated by LIE technique. Surface morphology and structural properties of nanostructures are characterized by using scanning electron microscopy and X‐ray diffraction (XRD). Photoluminescence (PL) measurement is also performed at room temperature by using He‐Cd laser (λ=325 nm) and Raman scattering has been investigated using Ar+ laser (λ=514 nm).
Findings
Surface morphology indicated that chemical reaction has been initiated with laser power density of 12 W/cm2, resulting in irregular structure. Micro‐columns are structured on surface with laser power density of 25 W/cm2. The pores structures are confined to smaller size, and the walls between the pore become extremely thin and shorter at 64 W/cm2 power density and 120 min irradiation time. PL spectra at room temperature for PS prepared at power density of 64 W/cm2 and irradiation time of 120 min shows the blue shift of PL at 400 nm and the full‐width and half maximum is about 60 nm. The broadening of the band gap energy occurs with a decrease of the crystallite size. The average diameter of nanosize Si crystallites is about 6‐10 nm. XRD indicated that the broadening in spectrum is due to the small size crystallites.
Originality/value
LIE processes have been used to produce high‐luminescent nanocrystallites with small size and size distribution, which is due to the quantum confinement effect.
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Aqsa Anjum and Mohammad Subhan
The study investigates the intention of adopting solar panels and incorporating renewable energy sources into the electrical mix, providing insightful information on the nuances…
Abstract
Purpose
The study investigates the intention of adopting solar panels and incorporating renewable energy sources into the electrical mix, providing insightful information on the nuances of this critical topic.
Design/methodology/approach
The study used online and offline surveys to gather information on rooftop solar panels from Indian homes. To get reliable findings, the collected responses were analyzed using structural equation modeling using Smart PLS version 3.5 and SPSS version 23.0.
Findings
The research examines sustainability difficulties, psychological issues and demographic considerations, yielding a variety of conclusions. Low compatibility and high perceived cost have a detrimental influence on adoption intentions, emphasizing the importance of integrating consumer perceptions with technology while addressing cost concerns. Conversely, relative advantage, awareness, environmental concern, facilitating conditions and observability positively influenced the adoption.
Practical implications
The study underscores the importance of highlighting benefits, raising awareness, providing necessary resources and showcasing visible instances of technology use. By revealing the connection between different factors, the study offers a roadmap for policymakers and stakeholders to accelerate the transition toward sustainable energy practices.
Originality/value
To the best of the authors' knowledge, this study is one of the first to propose an integration of the Theory of Planned Behavior (TPB), the Diffusion of Innovations Theory (DOI) and the Unified Theory of Acceptance and Use of Technology (UTAUT), alongside various independent variables. The research offers a comprehensive perspective on factors that facilitate and obstruct the usage of solar energy.
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Asmiet Ramizy, Wisam J. Aziz, Z. Hassan, Khalid Omar and K. Ibrahim
The purpose of this paper is to describe how fabricate solar cell based‐on porous silicon (PS) prepared by electrochemical etching process is fabricated and the effect of porosity…
Abstract
Purpose
The purpose of this paper is to describe how fabricate solar cell based‐on porous silicon (PS) prepared by electrochemical etching process is fabricated and the effect of porosity layer on the solar cell performance is investigated.
Design/methodology/approach
The techniques used include SiO2 thermal oxidation, ZnO/TiO2 sputtering deposition and PS prepared by electrochemical etching. Surface morphology and structural properties of porous Si were characterized by using scanning electron microscopy. Photoluminescence and Raman spectroscopy measurements were also performed at room temperature. Current‐voltage measurements of the fabricated solar cell were taken under 80 mW/cm2 illumination conditions. Optical reflectance was obtained by using optical reflectometer (Filmetrics‐F20).
Findings
Pore diameter and microstructure are dependent on anodization condition such as HF: ethanol concentration, duration time, temperature, and current density. On other hand, a much more homogeneous and uniform distribution of pores is obtained when compared with other wafer prepared with different electrolyte composition.
Originality/value
PS is found to be an excellent anti‐reflection coating against incident light when it is compared with another anti‐reflection coating and exhibits good light‐trapping of a wide wavelength spectrum which produce high efficiency solar cells (11.23 per cent).
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Rabia H. Haddad, Bushra Kh. Alhusamiah, Razan H. Haddad, Mo’tasem M. Aldaieflih, Khalid Yaseen, Younis H. Abuhashish, Ayman M. Hamdan-Mansour and Jafar A. Alshraideh
This study aims to evaluate and summarize the effectiveness of cognitive behavioral therapy (CBT) and internet-based CBT (ICBT) interventions on relapse prevention and severity of…
Abstract
Purpose
This study aims to evaluate and summarize the effectiveness of cognitive behavioral therapy (CBT) and internet-based CBT (ICBT) interventions on relapse prevention and severity of symptoms among individuals with major depressive disorder (MDD). CBT is one of the most used and suggested interventions to manage MDD, whereas ICBT is a novel effective proposed approach.
Design/methodology/approach
The review was conducted following the preferred reporting items for systematic review and meta-analysis protocol. A comprehensive and extensive search was performed to identify and evaluate the relevant studies about the effectiveness of CBT and ICBT on relapse prevention and severity of symptoms among patients with MDD.
Findings
A total of eight research studies met the inclusion criteria and were included in this systematic review. RCT studies were conducted to assess and evaluate the effectiveness of CBT and ICBT on relapse prevention and severity of symptoms among patients with MDD. It has been found that CBT is a well-supported and evidently based effective psychotherapy for managing depressive symptoms and reducing the relapse and readmission rate among patients diagnosed with MDD. The ICBT demonstrated greater improvements in depressive symptoms during major depressive episodes among patients with MDDS. The ICBT program had good acceptability and satisfaction among participants in different countries.
Research limitations/implications
Despite the significant findings from this systematic review, certain limitations should be acknowledged. First, it is important to note that all the studies included in this review were exclusively conducted in the English language, potentially limiting the generalizability of the findings to non-English speaking populations. Second, the number of research studies incorporated in this systematic review was relatively limited, which may have resulted in a narrower scope of analysis. Finally, a few studies within the selected research had small sample sizes, which could potentially impact the precision and reliability of the overall conclusions drawn from this review. The authors recommend that nurses working in psychiatric units should use CBT interventions with patients with MDD.
Practical implications
This paper, a review of the literature gives an overview of CBT and ICBT interventions to reduce the severity of depressive symptoms and prevent patients’ relapse and rehospitalization and shows that CBT interventions are effective on relapse prevention among patients with MDD. In addition, there is still no standardized protocol to apply the CBT intervention in the scope of reducing the severity of depressive symptoms and preventing depression relapse among patients with major depressive disorder. Further research is needed to confirm the findings of this review. Future research is also needed to find out the most effective form and contents of CBT and ICBT interventions for MDD.
Social implications
CBT is a psychological intervention that has been recommended by the literature for the treatment of major depressive disorder (MDD). It is a widely recognized and accepted approach that combines cognitive and behavioral techniques to assist individuals overcome their depressive symptoms and improve their overall mental well-being. This would speculate that effectiveness associated with several aspects and combinations of different approaches in CBT interventions and the impact of different delivery models are essential for clinical practice and appropriate selection of the interventional combinations.
Originality/value
This systematic review focuses on the various studies that explore the effectiveness of face-to-face CBT and ICBT in reducing depressive symptoms among patients with major depressive disorder. These studies were conducted in different countries such as Iran, Australia, Pennsylvania and the USA.
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