Ultraviolet Detectors Based on Wide Bandgap Semiconductor Nanowire: A Review

Abstract

Ultraviolet (UV) detectors have attracted considerable attention in the past decade due to their extensive applications in the civil and military fields. Wide bandgap semiconductor-based UV detectors can detect UV light effectively, and nanowire structures can greatly improve the sensitivity of sensors with many quantum effects. This review summarizes recent developments in the classification and principles of UV detectors, i.e., photoconductive type, Schottky barrier type, metal-semiconductor-metal (MSM) type, p-n junction type and p-i-n junction type. The current state of the art in wide bandgap semiconductor materials suitable for producing nanowires for use in UV detectors, i.e., metallic oxide, III-nitride and SiC, during the last five years is also summarized. Finally, novel types of UV detectors such as hybrid nanostructure detectors, self-powered detectors and flexible detectors are introduced.

ZnO‐Based Ultraviolet Photodetectors with Tunable Spectral Responses

“…Ultraviolet (UV) photodetectors are crucial for the military and civilian applications such as missile detection, flame warning, environmental monitoring, etc . Visible‐blind UV detection in established commercial photodetectors is achieved by using silicon‐based photodiodes combined with optical filters and wide bandgap semiconductors . However, the filter‐based technique significantly increases fabricating cost and structural complexity, limiting reduction in feature size of the photodetectors.…”

“…[1][2][3] Visible-blind UV detection in established commercial photodetectors is achieved by using silicon-based photodiodes combined with optical filters [4] and wide bandgap semiconductors. [5,6] However, the filter-based technique significantly increases fabricating cost and structural complexity, limiting reduction in feature size of the photodetectors. Furthermore, equipping filters introduce new optical interfaces, which reduces the intensity of incident light as well as impacts negatively on responsivity.…”

Bipolar photoresponse ultraviolet photodetectors based on ZnO nanowires

“…Owing to the direct bandgap of 3.3 eV, ZnO only absorbs ultraviolet photons (λ<400 nm) leading to a high ultraviolet-to-visible rejection ratio [25]. Moreover, zinc oxide and titanium dioxide nanocrystals are very promising for employing in the optoelectronic devices, including ultraviolet photodetectors, because they benefit from a large surface-tovolume ratio, ultrahigh sensitivity, and prolonged photo-carrier lifetime which results in the high photoconductive gain [14,[26][27][28][29][30][31][32][33].…”

Dual‐Channel Solar‐Blind UV Photodetector Based on β‐Ga2O3

“…Solar‐blind UV photodetectors are naturally attractive for multiple applications, requiring the visible and infrared radiation (IR) regions of solar radiation not to trigger any response of the device. Such applications particularly include engine control, solar UV monitoring, UV astronomy, lithography aligners, secure space‐to‐space communications, detection of missiles, healthcare (monitoring UVA exposure for skin cancer), forensics, flame, and chemical sensing, as well as other areas where UV detectors find use …”

“…However, despite their wide applicability and maturity, these detectors are not inherently solar blind, and hence necessitate the use of filters to reject the corresponding wavelengths. Wide band gap semiconductors are sensitive to UV by their band‐to‐band absorption and are, therefore, naturally attractive for applications …”