Nurul Fadzlin Hasbullah

Bio: Nurul Fadzlin Hasbullah is an academic researcher from International Islamic University Malaysia. The author has contributed to research in topics: Irradiation & Diode. The author has an hindex of 7, co-authored 66 publications receiving 165 citations. Previous affiliations of Nurul Fadzlin Hasbullah include University of Sheffield & Islamic University.

Correlation between defect density and current leakage in InAs∕GaAs quantum dot-in-well structures

Abstract: We present a study of InAs∕GaAs quantum dot-in-well (DWELL) material using transmission electron microscopy and leakage current-voltage measurements. The spacer layers between the DWELL layers have a variety of annealing and growth temperatures. We show that there is a strong correlation between spacer layer, annealing temperature, defect density, and these leakage currents, with the most defective sample having 30 times more defects and a leakage current several orders of magnitude above that of the least defective. Cross section transmission electron microscope (TEM) shows that surface roughness above defective dots is responsible for the high defect densities. However, even in the best sample the reverse bias leakage current is several orders of magnitude above that typically seen in quantum well materials and a measurable density of defective dots are observed in planar view TEM.

Weibull Probability Distribution of Wind Speed for Gaza Strip for 10 Years

Abstract: The need of clean and renewable energy, as well as the power shortage in Gaza strip with few wind energy studies conducted in Palestine, provide the importance of this paper. Probability density function is commonly used to represent wind speed frequency distributions for the evaluation of wind energy potential in a specific area. This study shows the analysis of the climatology of the wind profile over the State of Palestine; the selections of the suitable probability density function decrease the wind power estimation error percentage. A selection of probability density function is used to model average daily wind speed data recorded at for 10 years in Gaza strip. Weibull probability distribution function has been estimated for Gaza based on average wind speed for 10 years. This assessment is done by analyzing wind data using Weibull probability function to find out the characteristics of wind energy conversion. The wind speed data measured from January 1996 to December 2005 in Gaza is used as a sample of actual data to this study. The main aim is to use the Weibull representative wind data for Gaza strip to show how statistical model for Gaza Strip over ten years. Weibull parameters determine by author depend on the pervious study using seven numerical methods, Weibull shape factor parameter is 1.7848, scale factor parameter is 4.3642 ms-1, average wind speed for Gaza strip based on 10 years actual data is 2.95 ms-1 per a day so the behavior of wind velocity based on probability density function show that we can produce energy in Gaza strip.

Dependence of the Electroluminescence on the Spacer Layer Growth Temperature of Multilayer Quantum-Dot Laser Structures

Abstract: Electroluminescence (EL) measurements have been performed on a set of In(Ga)As-GaAs quantum-dot (QD) structures with varying spacer layer growth temperature. At room temperature and low injection current, a superlinear dependence of the integrated EL intensity (IEL) on the injection current is observed. This superlinearity decreases as the spacer layer growth temperature increases and is attributed to a reduction in the amount of nonradiative recombination. Temperature-dependent IEL measurements show a reduction of the IEL with increasing temperature. Two thermally activated quenching processes, with activation energies of ~ 157 meV and ~ 320 meV, are deduced and these are attributed to the loss of electrons and holes from the QD ground state to the GaAs barriers. Our results demonstrate that growing the GaAs barriers at higher temperatures improves their quality, thereby increasing the radiative efficiency of the QD emission.

Dark current mechanisms in quantum dot laser structures

Abstract: Current-voltage measurements have been performed on InAs/InGaAs/GaAs quantum dot structures with varying growth and design parameters. These measurements show that the forward and reverse bias dark currents decrease with increasing spacer growth temperature, however, they are relatively insensitive to the number of periods of the quantum dot layers. Temperature dependent current-voltage measurements show that the mechanism that governs the reverse bias leakage current is due to generation-recombination via mid-band traps assisted by the Frenkel-Poole emission of carriers from these traps.

Neutron Radiation Effects on the Electrical Characteristics of InAs/GaAs Quantum Dot-in-a-Well Structures

Abstract: This paper studies the effects of neutron radiation on the electrical behaviour and leakage current mechanism of quantum dot-in-a-well (DWELL) semiconductor diodes with fluence ranging from 3 to $9 \times 10^{13}~\hbox{neutron/cm}^{2}$ . After neutron irradiation, the forward bias and reverse bias leakage currents showed significant rise approximately of up to two orders of magnitude which is believed to be attributed to the presence of displacement damage induced traps. The ideality factor of the forward bias leakage current corresponding to all neutron fluence irradiations were found to be close to 2, suggesting that the forward bias current mechanism is largely due to trap-assisted generation-recombination (TAGR) of carriers. Subsequently, it is also observed that the capacitances reduced after irradiations which were further shown to be due to the deep carrier trapping effects and the Neutron Transmutation Doping effects (NTD). From the temperature dependence measurements, it is found that the reverse bias leakage current mechanisms of the irradiated samples are primarily attributed to two process; TAGR of carriers with emission from the traps assisted by the Frenkel-Poole (F-P). The traps due to both mechanisms were derived and shown to increase with neutron fluence.

[Award for Best Review Paper Speech](30min.)Wide-Bandgap Semiconductor Materials: For Their Full Bloom

Abstract: Wide-bandgap semiconductors are expected to be applied to solid-state lighting and power devices, supporting a future energy-saving society. While GaN-based white LEDs have rapidly become widespread in the lighting industry, SiC- and GaN-based power devices have not yet achieved their popular use, like GaN-based white LEDs for lighting, despite having reached the practical phase. What are the issues to be addressed for such power devices? In addition, other wide-bandgap semiconductors such as diamond and oxides are attracting focusing interest due to their promising functions especially for power-device applications. There, however, should be many unknown phenomena and problems in their defect, surface, and interface properties, which must be addressed to fully exploit their functions. In this review, issues of wide-bandgap semiconductors to be addressed in their basic properties are examined toward their ?full bloom?.

Reliability of InAs/GaAs Quantum Dot Lasers Epitaxially Grown on Silicon

Abstract: We present the first reliability study of InAs/GaAs self-assembled quantum dot lasers epitaxially grown on Ge/Si substrates. Some devices maintain lasing oscillation after more than 2700 h of constant current stress at 30 °C, longer than any previous life tests of GaAs lasers epitaxially grown on silicon. No catastrophic failures were observed. The lasers were characterized to gain insight on the aging mechanism.

Current and Future Challenges

Abstract: In Chapter 1, we summarized the concepts of equating, scaling, and linking In subsequent chapters, these concepts were further developed and elaborated. In Chapter 11 we focus on some current and future challenges in each of these areas.

Electronic circuit analysis and design

Abstract: Fundamentals of Electronic Circuit Analysis and DesignMicrowave Active Circuit Analysis and DesignElectronic Circuits (Sie) 3EIntroduction to Electrical Circuit AnalysisFoundations of Analog and Digital Electronic CircuitsFast Analytical Techniques for Electrical and Electronic CircuitsAnalog Circuit DesignElectronic CircuitsIntroduction to Linear Circuit Analysis and ModellingMicroelectronicsIntroduction to Circuit Analysis and DesignPower ElectronicsMicroelectronics Circuit Analysis and DesignElectronic Circuit Analysis and DesignComputer Methods for Circuit Analysis and DesignAnalysis and Design of Electronic Circuits Using PCsFundamentals of Electronics: Book 1Microelectronic Circuits: Analysis and DesignElectronic Circuit Analysis:Tolerance Design of Electronic CircuitsElectronics and Circuit Analysis Using MATLABIntuitive Analog Circuit DesignElectronic Circuit Analysis and DesignComputer Methods for Circuit Analysis and DesignElectronic Circuit Analysis and DesignCircuit AnalysisIntroduction to Electronic Circuit DesignAdvanced Electronic Circuit DesignElectronic Circuit Analysis and DesignMosfet Modeling for Circuit Analysis and DesignElectronic CircuitsCircuit Analysis For DummiesMicroelectronic CircuitsElectronic Circuit Analysis and DesignElectronic Circuit AnalysisElectronic Circuit Analysis and DesignElectronic Circuit DesignElectrical Circuit Analysis and DesignCircuitsElectronic Circuit Analysis and Design

A Review: Photonic Devices Used for Dosimetry in Medical Radiation.

Abstract: Numerous instruments such as ionization chambers, hand-held and pocket dosimeters of various types, film badges, thermoluminescent dosimeters (TLDs) and optically stimulated luminescence dosimeters (OSLDs) are used to measure and monitor radiation in medical applications. Of recent, photonic devices have also been adopted. This article evaluates recent research and advancements in the applications of photonic devices in medical radiation detection primarily focusing on four types; photodiodes – including light-emitting diodes (LEDs), phototransistors—including metal oxide semiconductor field effect transistors (MOSFETs), photovoltaic sensors/solar cells, and charge coupled devices/charge metal oxide semiconductors (CCD/CMOS) cameras. A comprehensive analysis of the operating principles and recent technologies of these devices is performed. Further, critical evaluation and comparison of their benefits and limitations as dosimeters is done based on the available studies. Common factors barring photonic devices from being used as radiation detectors are also discussed; with suggestions on possible solutions to overcome these barriers. Finally, the potentials of these devices and the challenges of realizing their applications as quintessential dosimeters are highlighted for future research and improvements.