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Enhanced Responsivity of ZnSe‐Based Metal–Semiconductor–Metal Near‐Ultraviolet Photodetector via Impact Ionization (Phys. Status Solidi RRL 2/2018)

2018; Wiley; Volume: 12; Issue: 2 Linguagem: Inglês

10.1002/pssr.201870305

1862-6270

Vadim P. Sirkeli, Oktay Yilmazoglu, Ahid S. Hajo, Natalia Nedeoglo, D. D. Nedeoglo, Sascha Preu, Franko Küppers, H.L. Hartnagel,

Chalcogenide Semiconductor Thin Films

Ultraviolet (UV) photodetectors are of special interest in view of their potential applications in medicine, biology, space, and telecommunication, including ozone layer monitoring, high temperature flame detection, nitrogen oxide gas-sensing and personal UV exposure dosimetry. Most commercial UV photodetectors are based on silicon or gallium arsenide semiconductors, which require a filter to eliminate visible and infrared light, and which could also be damaged under intense UV radiation due to induced aging defects. To overcome these problems of conventional commercial UV photodetectors, researchers from the Darmstadt University of Technology (Darmstadt, Germany), Comrat State University (Comrat, Moldova) and Moldova State University (Chisinau, Moldova) used a high-resistivity bulk zinc selenide (ZnSe) semiconductor material grown by vapor phase technique as active layer for the fabrication of near-ultraviolet photodetectors with metal-semiconductor-metal (MSM) structures operating at room temperature (see article no. 1700418 by Sirkeli et al.). The authors found that the fabricated ZnSe-based UV photodetectors have enhanced sensitivity and responsivity due to the used internal mechanism of multiplication of charge carriers, called impact ionization, which is possible by the application of sufficiently high voltages to the metal electrodes, such that the electric field in the semiconductor is just below breakdown.