Shahrir Rizal Kasjoo
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Preferred name
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

Research Output

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  • Publication
    Remazol orange dye sensitized solar cell
    ( 2017-01-03)
    Siti Salwa Mat Isa
    ;
    Muhammad Mahyiddin Ramli
    ;
    Nor Azura Malini Ahmad Hambali
    ;
    Muda M.R.
    ;
    Shahrir Rizal Kasjoo
    ;
    Muammar Mohamad Isa
    ;
    Nurul Izza Mohd Nor
    ;
    Norhawati Ahmad
    ;
    Nazuhusna Khalid
    ;
    Nur M. Selamat
    ;
    Nur Asyikin Mohd Anhar
    Water based Remazol Orange was utilized as the dye sensitizer for dye sensitized solar cell. The annealing temperature of TiO2 working electrode was set at 450 °C. The performance of the device was investigated between dye concentrations of 0.25 mM and 2.5 mM at three different immersion times (3, 12 and 24 hours). The adsorption peak of the dye sensitizer was evaluated using UV-Vis-Nir and the device performance was tested using solar cell simulator. The results show that the performance was increased at higher dye concentration and longer immersion time. The best device performance was obtained at 0.2% for dye concentration of 2.5 mM immersed at 24 hours.
  • 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
    Non-linear analysis of Self-Switching Diodes as microwave rectifiers
    ( 2017-01-01)
    Shahrir Rizal Kasjoo
    ;
    Zulfadhli Zailan
    ;
    Sanna Taking
    ;
    Wan Zuki Azman Wan Muhamad
    ;
    Muammar Mohamad Isa
    ;
    Arshad M.
    A planar device known as the Self-Switching Diode (SSD) has been demonstrated as a high-speed rectifier, up to terahertz frequencies. The rectifying properties of SSD are dependent on a nonlinear current-voltage characteristic of the device. In this research, the rectification of two SSD rectifiers has been reported and their performances were evaluated. The observed results showed a good agreement with the nonlinear theoretical analysis of both rectifiers by means of a Taylor series which can be utilized in improving the rectifying performance of any diode-based rectifier specifically for diodes with tunable threshold voltage such as SSDs.
  • Publication
    Review of mixer design for low voltage - Low power applications
    ( 2017-09-26)
    Nurulain D.
    ;
    Musa F.A.S.
    ;
    Muammar Mohamad Isa
    ;
    Norhawati Ahmad
    ;
    Shahrir Rizal Kasjoo
    A mixer is used in almost all radio frequency (RF) or microwave systems for frequency translation. Nowadays, the increase market demand encouraged the industry to deliver circuit designs to create proficient and convenient equipment with very low power (LP) consumption and low voltage (LV) supply in both digital and analogue circuits. This paper focused on different Complementary Metal Oxide Semiconductor (CMOS) design topologies for LV and LP mixer design. Floating Gate Metal Oxide Semiconductor (FGMOS) is an alternative technology to replace CMOS due to their high ability for LV and LP applications. FGMOS only required a few transistors per gate and can have a shift in threshold voltage (VTH) to increase the LP and LV performances as compared to CMOS, which makes an attractive option to replace CMOS.
  • 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
    Numerical Simulation and Characterization of Silicon Based OR Logic Gate Operation Using Self-Switching Device
    ( 2021-01-01)
    Goh Y.X.
    ;
    Zakaria N.F.
    ;
    Tan Y.L.
    ;
    Shahrir Rizal Kasjoo
    ;
    Shaari S.
    ;
    Muammar Mohamad Isa
    ;
    Singh A.K.
    Logic gates are the main components inside the integrated circuit used for almost every technological application. Nowadays, in order to enhance the performance of the smart device, while targeting in cut down of the fabrication cost and achieve low power consumption, lithography-based VLSI design technology on silicon are still being widely applied. Hence, an OR gate structure, a silicon based self-switching device (SSD) is introduced and investigated in this project. Such device is believed capable to act as an alternative for a low-powered logic gate application, suitable for CMOS devices. The SSD has an advantage in term of simplicity in fabrication process with a very low threshold voltage. Since SSD characteristics is similar to a conventional diode characteristic, the gate is designed in ATLAS Silvaco device simulator based on a diode logic to perform OR logic function after a validation of the physical and materials parameters. The electrical characterization and structural analysis were also done to observe the electrical performance and physical condition in the device. The simulated design showed a good OR logic output response with the inputs, and acceptable output ranged from around 4.5 to 4.8 V with 5 V HIGH inputs. The results from this OR gate characterization may assist in developing the logic gate for device integration and may act as a reference for future complex integrated circuit design.
  • Publication
    Improved rectification performance and terahertz detection in hybrid structure of self-switching device (SSD) and planar barrier diode (PBD) using two-dimensional device simulation
    ( 2020-01-01)
    Nor Farhani Zakaria
    ;
    Shahrir Rizal Kasjoo
    ;
    Muammar Mohamad Isa
    ;
    Zarimawaty Zailan
    ;
    Mohd Khairuddin Md Arshad
    ;
    Song A.
    Recently, simulations of In0.48Ga0.52As-based Planar Barrier Diode (PBD) and Self- Switching Device (SSD) as millimeter-wave rectifiers were reported. Both PBD and SSD have a planar structure, but with different insulating shapes and working principles. In this work, a hybrid structure of the reported PBD and SSD in a parallel configuration is proposed, to exploit the advantages of each device. The advantages of high rectifying properties in the SSD and fast switching rate of the PBD are combined in this hybrid structure in order to obtain an improved rectification performance at zero-bias in the near terahertz frequency region. Analysis of the curvature co-efficient, γ, which is defined as the ratio of the second order to the first order derivative of the device’s I-V function was performed to evaluate the rectification performance. AC transient analyses were then executed in various frequencies to imitate the high-frequency signal inputs. By using this hybrid structure, the highest value of γ achieved has been improved to ~19 V-1 at 70 mV, and ~6 V-1 at zero- bias (compared to the previous results on PBDs). The estimated cut-off frequency obtained was ~360 GHz (0.36 THz), operating at zero-bias.
      5  38
  • 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.
      37  9
  • Publication
    Terahertz Imaging Using Nanorectifier-Based Detectors and Broadband Thermal Sources
    ( 2023-12-01)
    Shahrir Rizal Kasjoo
    ;
    Singh A.K.
    ;
    Balocco C.
    ;
    Song A.
    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).
      43  1
  • Publication
    Self-switching diodes as RF rectifiers: Evaluation methods and current progress
    ( 2019-06-01)
    Zakaria N.
    ;
    Shahrir Rizal Kasjoo
    ;
    Isa M.
    ;
    Zarimawaty Zailan
    ;
    Arshad M.
    ;
    Sanna Taking
    In the advancement of the Internet of Things (IoT) applications, widespread uses and applications of devices require higher frequency connectivity to be explored and exploited. Furthermore, the size, weight, power and cost demands for the IoT ecosystems also creates a new paradigm for the hardware where improved power efficiency and efficient wireless transmission needed to be investigated and made feasible. As such, functional microwave detectors to detect and rectify the signals transmitted in higher frequency regions are crucial. This paper reviewed the practicability of self switching diodes as Radio Frequency (RF) rectifiers. The existing methods used in the evaluation of the rectification performance and cut-off frequency are reviewed, and current achievements are then concluded. The works reviewed in this paper highlights the functionality of SSD as a RF rectifier with design simplicity, which may offer cheaper alternatives in current high frequency rectifying devices for application in low-power devices.
      31  3