Volume 21, Issue 1 (7-2024)
lmj 2024, 21(1): 7-14 |
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Khodaverdizadeh M, asgari A. Numerical Investigation of the Responsivity in Low-Toxicity Mid-Infrared Detectors Based on Ag2Se-PbS Quantum Dots. lmj 2024; 21 (1) :7-14
URL: http://icml.ir/article-1-633-en.html
URL: http://icml.ir/article-1-633-en.html
Abstract: (481 Views)
Introduction: Optical sensors are an integral part of various devices in the field of biomedical diagnostics. In the meantime, photonic technologies have gained great popularity for use as sensors in medical applications and human health monitoring due to their many advantages such as high sensitivity, the possibility of integration with electronic devices, suitable compactness of the device, metal-free operation, cheap cost, and electromagnetic safety that photonic technologies provide, justify the need to study in the field of optical sensors.
Analysis method: In this study, the effect of the composition percentage of PbS and Ag2Se quantum dots, as well as the changes in the diameter and film doping density of Ag2Se quantum dots in the active region at different temperatures to maximize the responsivity has been studied. To achieve the responsivity of the photodetector based on the structure of quantum dots, first by solving the self-consistent Schrödinger and Poisson equations with the finite difference method, the electron density in each level and potential profile is obtained and the responsivity of the photodetector is calculated.
Results: The obtained results show that with the increasing percentage of PbS quantum dots compared to Ag2Se quantum dots, the responsivity of the device decreases. By increasing the film doping density of the Ag2Se quantum dots, initially due to the increase of carriers for optical excitation, the responsivity increases, and after reaching the maximum point, the responsivity decreases because of the increase of carrier recombination. The responsivity increases with the increase in the diameter of Ag2Se quantum dots due to the quantum confinement effects, carrier escape, and tunneling effects and decreases after reaching the maximum point.
Conclusion: Nowadays, increasing the quantum efficiency and optical responsivity of such biomedical optical sensors is a great challenge for medical device engineers. In general, maximizing the responsivity improves the performance, accuracy, and efficiency of the photodetectors, and this can be achieved by engineering the structure of the devices.
Analysis method: In this study, the effect of the composition percentage of PbS and Ag2Se quantum dots, as well as the changes in the diameter and film doping density of Ag2Se quantum dots in the active region at different temperatures to maximize the responsivity has been studied. To achieve the responsivity of the photodetector based on the structure of quantum dots, first by solving the self-consistent Schrödinger and Poisson equations with the finite difference method, the electron density in each level and potential profile is obtained and the responsivity of the photodetector is calculated.
Results: The obtained results show that with the increasing percentage of PbS quantum dots compared to Ag2Se quantum dots, the responsivity of the device decreases. By increasing the film doping density of the Ag2Se quantum dots, initially due to the increase of carriers for optical excitation, the responsivity increases, and after reaching the maximum point, the responsivity decreases because of the increase of carrier recombination. The responsivity increases with the increase in the diameter of Ag2Se quantum dots due to the quantum confinement effects, carrier escape, and tunneling effects and decreases after reaching the maximum point.
Conclusion: Nowadays, increasing the quantum efficiency and optical responsivity of such biomedical optical sensors is a great challenge for medical device engineers. In general, maximizing the responsivity improves the performance, accuracy, and efficiency of the photodetectors, and this can be achieved by engineering the structure of the devices.
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Received: 2024/04/21 | Accepted: 2024/06/3 | Published: 2024/07/21
Received: 2024/04/21 | Accepted: 2024/06/3 | Published: 2024/07/21
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