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
Now showing 1 - 5 of 5
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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).

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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.

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Simulation of InGaAs-based self-switching diodes as sub-terahertz rectifiers

2022-12 , Faradilla Aziz , Shahrir Rizal Kasjoo , Nor Farhani Zakaria , Fauzi Packeer , A.K. Singh

Abstract. A self-switching device (SSD) is a new device concept -which can be simply realized by forming insulating trenches into a semiconductor layer, using a single nanolithography process. SSDs can be utilized as rectifiers since the device's current-voltage (I-V) characteristic is comparable to that of a conventional diode. The simulation of two InGaAsbased SSDs with parallel connection using ATLAS device simulator for similar and different lengths of both SSDs (L1 and L2) is presented in this paper. The simulation results show that the InGaAs-based SSDs are able to operate up to sub-terahertz (THz) frequencies. As expected, lowering either L1 or L2 will not only increase the device’s cut-off frequency, fc, but also degrading the device’s rectification performance (i.e., reducing the value of curvature coefficient, γ). The highest cut-off frequency achieved in this work was 0.27 THz with γ ~18V-1 when L1 = 0.8 μm and L2 = 0.4 μm.

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Publication

Noise Properties of Unipolar Nanodiodes at Elevated Temperatures

2021-12-01 , Shahrir Rizal Kasjoo , Singh A.K. , Balocco C. , Song A.

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.

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Publication

Terahertz detection using nanorectifiers

2013-12 , Shahrir Rizal Kasjoo , Ai Min Song

We report on the low-temperature detection of free-space radiation at 1.5 THz using a unipolar nanodiode, known as the self-switching diode (SSD), coupled with a spiral microantenna. The SSD, based on an asymmetric nanochannel, has a diode-like characteristic that can be utilized in rectifying high-frequency electrical signals. The truly planar structure of the SSD not only provides intrinsically low parasitic capacitance that enables rectification at ultrahigh speed, but also allows the fabrication of a large SSD array in parallel without the need for interconnection layers. The extrinsic voltage responsivity of the SSD-based detector achieved was ∼15.6 V/W, but the estimated intrinsic voltage responsivity was ∼45 kV/W.

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