Shahrir Rizal Kasjoo
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Shahrir Rizal Kasjoo
Official Name
Shahrir Rizal, Kasjoo
Alternative Name
Kasjoo, S.
Kasjoo, Shahrir R.
Kasjoo, S. R.
Shah K.
Main Affiliation
Scopus Author ID
36809748400
Researcher ID
ABI-6061-2020

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  • Publication
    Simulation and characterization of an inverter logic gate by utilizing InGaAs-based planar devices
    ( 2023-12)
    Faradilla Aziz
    ;
    Shahrir Rizal Kasjoo
    ;
    Nor Farhani Zakaria
    ;
    Fauzi Packeer
    ;
    A. K. Singh
    Electronic circuits known as logic gates can perform basic logical operations like inverters, AND, and OR gates. These logic gates serve as the basis for digital electronics, and they are a common component in various electronic devices, such as computers, smartphones, and other types of digital systems. This research presents an inverter logic gate made of planar devices, which have significantly simpler structures than multi-layered transistors and diodes, namely the self-switching diode (SSD) and side-gated transistor (SGT). The inverter logic gate is realized by simply connecting both SSD and SGT in parallel. The electrical characteristics and performances of the inverter logic gate are assessed based on InGaAs material using SILVACO Inc.'s ATLAS device simulator software. The simulation results show that the functionality of the proposed planar inverter is comparable to that of a conventional inverter logic gate based on the standard truth table of the device. This has demonstrated the feasibility of building logic gates using a combination of SSDs and SGTs. In addition, the planar structure of SSD and SGT allows for a relatively low-cost device fabrication process as well as offering a high-frequency operation due to low parasitic elements in the devices.
  • Publication
    Comprehensive study on gate recess step for the fabrication of high-speed InGaAs/InAlAs/InP pHEMT
    ( 2017-01-03)
    Muammar Mohamad Isa
    ;
    Norhawati Ahmad
    ;
    Siti Salwa Mat Isa
    ;
    Muhammad Mahyiddin Ramli
    ;
    Nazuhusna Khalid
    ;
    Nurul Izza Mohd Nor
    ;
    Shahrir Rizal Kasjoo
    ;
    Missous M.
    We report a comprehensive etching study on the gate recess step for the fabrication of the novel high speed pHEMT devices. The experiments focused on the elimination of 'hump' structure as a result of an incomplete etching process at the InGaAs cap layer. In this work, two types of test samples were used, namely bulk InGaAs and epitaxial structure together with an etch stop layer. The result showed that the etch rate of bulk InGaAs is about 360 A/min and the percentage of dome height is consistent at approximately 25%. Meanwhile, the study on pHEMT epitaxial layer showed that the etching time of 3 minutes is sufficient in order to completely remove the cap layer. Gate leakage current of magnitude more than 10 times lower is observed on the devices that engaging Succinic Acid as the gate recess etching agent. The optimized processing steps will tailor for highly reproducible pHEMT fabrication process for high speed applications.
  • Publication
    A brief overview of detectors used for terahertz imaging systems
    ( 2020-01-08)
    Shahrir Rizal Kasjoo
    ;
    Mohd Mokhar, Mohd Bazli
    ;
    Nor Farhani Zakaria
    ;
    Nurjuliana Juhari
    This paper presents a short review on terahertz imaging systems based on several types of technology used in the terahertz detection schemes. Some commercial products from ThruVision Systems Limited Company have utilized GaAs Schottky diode detector at 0.25 THz to produce passive terahertz images for public and homeland security. On the other hand, TeraSense Group Incorporated Company has developed and invented a ground-breaking technology which employs sensor consisting of a matrix of plasmonic semiconductor detectors in their latest products to generate terahertz images in the 0.1 - 1.0 THz frequency range. Recently, the utilization of two-terminal unipolar nanodiodes, known as the self-switching diodes (SSDs), as terahertz detectors has shown promising results. The planar structure of SSD not only enables the device to operate at high frequencies due to low intrinsic parasitic capacitance, but also allows the realization of the device using only a single lithography step. This makes the fabrication process of SSDs faster, more simple, and at lower cost when compared to other electronic devices such as Schottky diodes. The development and recent achievement of SSDs as terahertz detectors are also presented in this paper.
  • Publication
    Noise properties of unipolar nanodiodes at elevated temperatures
    ( 2021-12)
    Shahrir Rizal Kasjoo
    ;
    Arun K. Singh
    ;
    Claudio Balocco
    ;
    Aimin Song
    A unipolar nanodiode known as the self-switching diode has been demonstrated as a room-temperature terahertz detector, with its noise-equivalent-power value comparable to those of the state-of-the-art Schottky diodes. Here, we study its performance at elevated temperatures and show an unusual reduction in low-frequency noise, which may be useful for practical applications. The experiments suggest that the increased thermionic emissions result in the reduced device resistance and hence the lowered noise. The observed noise behavior appears to be in good agreement with Hooge’s mobility fluctuation theory.
  • Publication
    Numerical Simulation and Parameters Variation of Silicon Based Self-Switching Diode (SSD) and the Effect to the Physical and Electrical Properties
    ( 2020-12-14)
    Tan Y.L.
    ;
    Zakaria N.F.
    ;
    Shahrir Rizal Kasjoo
    ;
    Safizan Shaari
    ;
    Muammar Mohamad Isa
    ;
    Mohd Khairuddin Md Arshad
    ;
    Rahim A.F.A.
    Investigation of SOI based self-switching diode (SSD) by numerical simulation for RF -DC harvesting application is presented. The rectification performance of the SSD is based on the curvature coefficient, ? and current responsivity, ß which are closely related to the I-V characteristic of a non-linear device. In this work, the structural parameters are varied to observe the electrical and physical characteristics with the aid of ATLAS Silvaco simulation tools. The rectification performance in each variation is then compared, with the highest value of ? and ß observed at 25.20 V and 12.60 V, respectively. By identifying and understanding these control factors and their effects, distinctive variations of the structural parameters by using a more deliberate optimization method can be proposed for further improvement on the rectification performance.
  • Publication
    An overview of semiconductor rectifier operating in the millimeter wave and terahertz region
    ( 2020-01-08)
    Mohd Mokhar, Mohd Bazli
    ;
    Shahrir Rizal Kasjoo
    ;
    Nurjuliana Juhari
    ;
    Nor Farhani Zakaria
    An imaging system operated at millimeter (MM) waves and terahertz (THz) frequencies can be used in many applications such as safety monitoring, public security, medical, healthcare and manufacturing. Typically, these systems utilize rectifying antenna (rectenna) to convert electromagnetic radiation into usable DC power which will be used to generate images. One of the main components of rectenna is the rectifier. Hence, this paper explores the current review on several semiconductor rectifiers that have been significantly deployed for MM-wave/THz imaging systems. This includes Schottky diodes, metal-insulator-metal (MIM) diodes, self-switching diodes (SSDs) and ballistic rectifiers (BRs). The rectifying performance of these devices are discussed in terms of their voltage responsivity and noise-equivalent power (NEP). The standard fabrication process of each device is also presented in this paper as well as their recent development and achievement as high-frequency rectifiers for MM-wave/THz imaging systems.
  • Publication
    Terahertz imaging using nanorectifier-based detectors and broadband thermal sources
    ( 2023-12)
    Shahrir Rizal Kasjoo
    ;
    Arun K. Singh
    ;
    Claudio Balocco
    ;
    Aimin Song
    Several terahertz imaging experiments have been conducted at room temperature using a self-switching diode (SSD) rectenna as a detector, and a broadband thermal source (at 610 °C) as a continuous-wave terahertz generator. Since the terahertz emission produced by the source is non-coherent with random polarizations and has a wide-ranging spectrum, the SSD-based rectenna employed in this work utilizes a planar spiral micro- antenna which has a circular polarization that able to effectively capture all incident radiation regardless of the angles. The antenna has been designed for a broadband frequency response in the range of 0.1-10 THz. This is to ensure the terahertz images produced are ascribed to the terahertz radiation collected by the antenna, but without eliminating the possibility of thermal effects at frequencies higher than the terahertz region. In order to further validate the results obtained, an Airy pattern experiment has been conducted. Based on this experiment, the effective frequency response of the SSD rectenna is estimated at 2.29 THz. The utilization of thermal source and micro-size rectenna in this work may pave the way to explore many opportunities in developing flexible, compact, and low-cost terahertz imaging systems without the use of expensive components (e.g., typically lasers are used as terahertz sources).
  • Publication
    Silicon Self-Switching Diode (SSD) as a Full-Wave Bridge Rectifier in 5G Networks Frequencies
    ( 2022-12-01)
    Yi Liang T.
    ;
    Nor Farhani Zakaria
    ;
    Shahrir Rizal Kasjoo
    ;
    Safizan Shaari
    ;
    Muammar Mohamad Isa
    ;
    Mohd Khairuddin Md Arshad
    ;
    Singh A.K.
    The rapid growth of wireless technology has improved the network’s technology from 4G to 5G, with sub-6 GHz being the centre of attention as the primary communication spectrum band. To effectively benefit this exclusive network, the improvement in the mm-wave detection of this range is crucial. In this work, a silicon self-switching device (SSD) based full-wave bridge rectifier was proposed as a candidate for a usable RF-DC converter in this frequency range. SSD has a similar operation to a conventional pn junction diode, but with advantages in fabrication simplicity where it does not require doping and junctions. The optimized structure of the SSD was cascaded and arranged to create a functional full-wave bridge rectifier with a quadratic relationship between the input voltage and outputs current. AC transient analysis and theoretical calculation performed on the full-wave rectifier shows an estimated cut-off frequency at ~12 GHz, with calculated responsivity and noise equivalent power of 1956.72 V/W and 2.3753 pW/Hz1/2, respectively. These results show the capability of silicon SSD to function as a full-wave bridge rectifier and is a potential candidate for RF-DC conversion in the targeted 5G frequency band and can be exploited for future energy harvesting application.
  • Publication
    Hybrid Statistical and Numerical Analysis in Structural Optimization of Silicon-Based RF Detector in 5G Network
    ( 2022-02-01)
    Yi Liang T.
    ;
    Nor Farhani Zakaria
    ;
    Shahrir Rizal Kasjoo
    ;
    Safizan Shaari
    ;
    Muammar Mohamad Isa
    ;
    Mohd Khairuddin Md Arshad
    ;
    Singh A.K.
    ;
    Sobri S.A.
    In this study, a hybrid statistical analysis (Taguchi method supported by analysis of variance (ANOVA) and regression analysis) and numerical analysis (utilizing a Silvaco device simulator) was implemented to optimize the structural parameters of silicon-on-insulator (SOI)-based self-switching diodes (SSDs) to achieve a high responsivity value as a radio frequency (RF) detector. Statistical calculation was applied to study the relationship between the control factors and the output performance of an RF detector in terms of the peak curvature coefficient value and its corresponding bias voltage. Subsequently, a series of numerical simulations were performed based on Taguchi’s experimental design. The optimization results indicated an optimized curvature coefficient and voltage peak of 26.4260 V−1 and 0.05 V, respectively. The alternating current transient analysis from 3 to 10 GHz showed the highest mean current at 5 GHz and a cut-off frequency of approximately 6.50 GHz, indicating a prominent ability to function as an RF detector at 5G related frequencies.
  • Publication
    A 12 GHz LC-VCO Implemented with S’ shape Inductor using silicon-on sapphire substrate
    ( 2022-12)
    Nazuhusna Khalid
    ;
    Aimi Noorliyana Hashim
    ;
    Nurul Izza Mohd Nor
    ;
    Shahrir Rizal Kasjoo
    ;
    Zaliman Sauli
    ;
    Mohd Norhafiz Hashim
    ;
    M.S Mispan
    A voltage-controlled oscillator (VCO) is an electronic oscillator whose oscillation frequency is controlled by a voltage input. In a VCO, low-phase noise while consuming less power is preferred. The tuning gain and noise in the control signal produce phase noise; more noise or tuning gain implies more phase noise. Sources of flicker noise (1/f noise) in the circuit, the output power level, and the loaded Q factor of the resonator are all crucial factors that influence phase noise. As a result, creating a resonator with a high Q-factor is essential for improving VCO performance. As a result, this paper describes a 12 GHz LC Voltage- Controlled Oscillator (VCO) employed with a ‘S’ shape inductor to improve phase noise and power performance. The phase noise for the VCO was reduced using a noise filtering technique. To reduce substrate loss and improve the Q factor, the inductor was designed on a high-resistivity Silicon-on Sapphire (SOS) substrate. At 12 GHz, the optimised S’ shape inductor has the highest Q-factor of 50.217. At 10 MHz and 100 MHz, the phase noise of the 12 GHz LC-VCO was -131.33 dBc/Hz and -156.71 dBc/Hz, respectively. With a 3.3 V power supply, the VCO core consumes 26.96 mW of power. Based on the findings, it is concluded that using an ‘S’ shape inductor in the VCO circuit will enable the development of low-cost, high-performance, very low-power system-on-chip wireless transceivers with longer battery life.