A metal electrode modification process for AlGaN-based metal-semiconductor-metal (MSM) photodetectors have been introduced to enhance the response of solar-blind ultraviolet (UV) light detection. The hexadecanethiol organic molecules are chemically adsorbed on the electrodes of high-Al-content AlGaN MSM solar-blind UV photodetectors, which can reduce the work function of the metal electrode and change the height of the Schottky barrier. This modification process significantly increases the photocurrent and responsivity of the device compared with the referential photodetector without modification. Additionally, the adverse effects caused by the surface state and polarization of the AlGaN materials are effectively reduced, which can be beneficial for improving the electrical performances of III-nitride-based UV photodetectors.
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http://dx.doi.org/10.1364/OE.418421 | DOI Listing |
We have designed a metal-semiconductor-metal (MSM) solar-blind ultraviolet (UV) photodetector (PD) by utilizing AlGaN/AlGaN/AlGaN heterostructures. The interdigital Ni/Au metal stack is deposited on the AlGaN layer to form Schottky contacts. The AlGaN hetero-epilayers with varying Al content contribute to the formation of a two-dimensional electron gas (2DEG) conduction channel and the enhancement of the built-in electric field in the AlGaN absorption layer.
View Article and Find Full Text PDFSolid-state self-powered UV detection is strongly required in various application fields to enable long-term operation. However, this requirement is incompatible with conventionally used metal-semiconductor-metal (MSM) UV photodetectors (PDs) due to the symmetric design of Schottky contacts. In this work, a self-powered MSM solar-blind UV-PD was realized using a lateral pn junction architecture.
View Article and Find Full Text PDFTraditional GaN-based metal-semiconductor-metal (MSM) photodetector (PD) features a symmetric structure, and thus a poor lateral carrier transport can be encountered, which can decrease the photocurrent and responsivity. To improve its photoelectric performance, we propose GaN-based MSM photodetectors with an AlGaN polarization layer structure on the GaN absorption layer. By using the AlGaN polarization layer, the electric field in the metal/GaN Schottky junction can be replaced by the electric fields in the metal/AlGaN Schottky junction and the AlGaN/GaN heterojunction.
View Article and Find Full Text PDFNanotechnology
January 2022
Department of Physics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India.
The appealing properties of tunable direct wide bandgap, high-temperature robustness and chemical hardness, make AlGaN a promising candidate for fabricating robust solar-blind photodetectors (PDs). In this work, we have utilized the optical phenomenon of localized surface plasmon resonance (LSPR) in metal nanoparticles (NPs) to significantly enhance the performance of solar-blind AlGaN metal-semiconductor-metal PDs that exhibit high-temperature robustness. We demonstrate that the presence of palladium (Pd) NPs leads to a remarkable enhancement by nearly 600, 300, and 462%, respectively, in the photo-to-dark current ratio (PDCR), responsivity, and specific detectivity of the AlGaN PD at the wavelength of 280 nm.
View Article and Find Full Text PDFSensors (Basel)
June 2021
School of Electronic and Electrical Engineering, Kyungpook National University, Daegu 41566, Korea.
Asymmetric metal-semiconductor-metal (MSM) aluminum gallium nitride (AlGaN) UV sensors with 24% Al were fabricated using a selective annealing technique that dramatically reduced the dark current density and improved the ohmic behavior and performance compared to a non-annealed sensor. Its dark current density at a bias of -2.0 V and UV-to-visible rejection ratio (UVRR) at a bias of -7.
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