Yazar "Alharbi, Seham R. N." seçeneğine göre listele

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    High-performance n – Si/p – SeO2 /p – SiO2 heterojunction photodetectors for potential application in visible light communication technology
    (Springer, 2023) Alharbi, Seham R. N.; Qasrawi, Atef Fayez; Algarni, Sabah E.
    Photodetectors suitable for visible light communication (VLC) technology were fabricated and characterized in this study. The photodetectors were designed using two p-type stacked layers of SeO2 and SiO2, which were coated onto n? type Si thin wafers. These stacked layers were deposited in a vacuum medium under a pressure of 10–5 mbar using the thermal evaporation technique. p-SiO2 thin layer enriched the hole concentration of p-SeO2 layer forming p+n type heterojunction and prevented SeO2 from environmental contaminations. The microstructure, surface morphology, and photoelectrical properties of the n-Si/p-SeO2/p-SiO2 (SSS) detectors were explored. It was observed that the SSS detectors exhibited biasing and light power dependent asymmetry. The asymmetry varied in the range of 77–178 as the light power increased from zero to 77 mW. In addition, the SSS photodetectors demonstrated a current responsivity, external quantum efficiency, and specific detectivity reaching values of 123 mA/W, 15.6%, and 1.3?×?1010 Jones, respectively. These values are considered adequate for VLC technology. Practical tests have shown that the device can transmit wireless square-wave pulses with frequencies up to approximately 10–100 kHz. The growth and decay response times were found to be 1.15 ms and 0.89 ms, respectively. The features of the SSS detectors make them suitable for use as light-controlled current rectifiers and VLC detectors.
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    Selenium oxide based laser sensors designed for optoelectronic applications
    (Springer, 2023) Alharbi, Seham R. N.; Qasrawi, Atef Fayez; Algarni, Sabah E.
    In this study, stacked layers of p? SeO2 and p? SiO2 were formed onto n? type silicon wafers to act as laser photosensors. The p? type stacked layers were fabricated using the thermal evaporation technique under a vacuum pressure of 10–5 mbar. Ag and Au thin films were used as Schottky contacts for p? SiO2 and n? Si, respectively. The energy band diagram of the device showed the presence of large conduction and valence band offsets that were sufficient for electron–hole separation. Practical tests using current–voltage characteristics indicated that in the dark, current transport was mostly dominated by diffusion and Richardson Schottky types of current conduction. These transport mechanisms led to a biasing-dependent rectification ratio, which increased by more than 149 times, 24 times, and ~?4 times under laser lights of wavelengths of 632 nm, 850 nm, and 1550 nm, respectively. The photosensors achieved high current responsivity (R˜ ) and external quantum efficiency (EQE %) reaching 0.54 A/W and 27.5%, respectively, under 632 nm-laser illuminations. The photosensors also showed acceptable values of R˜ and EQE % when irradiated with laser lights of wavelengths of 850 nm and 1550 nm. The proposed devices exhibited features such as a rectification ratio up to 104 and specific detectivity of ~?1010 Jones under laser light, making them suitable for wireless communication technology.