A microfabricated sun sensor using GaN-on-sapphire ultraviolet photodetector arrays

Abstract

A miniature sensor for detecting the orientation of incident ultraviolet light was microfabricated using gallium nitride (GaN)-on-sapphire substrates and semi-transparent interdigitated gold electrodes for sun sensing applications. The individual metal-semiconductor-metal photodetector elements were shown to have a stable and repeatable response with a high sensitivity (photocurrent-to-dark current ratio (PDCR) = 2.4 at -1 V bias) and a high responsivity (3200 A/W at -1 V bias) under ultraviolet (365 nm) illumination. The 3 × 3 GaN-on-sapphire ultraviolet photodetector array was integrated with a gold aperture to realize a miniature sun sensor (1.35 mm × 1.35 mm) capable of determining incident light angles with a ±45° field of view. Using a simple comparative figure of merit algorithm, measurement of incident light angles of 0° and 45° was quantitatively and qualitatively (visually) demonstrated by the sun sensor, supporting the use of GaN-based sun sensors for orientation, navigation, and tracking of the sun within the harsh environment of space.

III-Nitrides Resonant Cavity Photodetector Devices

“…This would imply that a 10 times larger photocurrent to dark current contrast ratio could be achieved with the resonant photodiodes, showing their superior performance. These values were close to those reported by several authors in the nitride-based photodetectors field [31].…”

Deep-ultraviolet integrated photonic and optoelectronic devices: A prospect of the hybridization of group III–nitrides, III–oxides, and two-dimensional materials

“…Compared to other wide bandgap materials (e.g., ZnO, SiC, and Ga 2 O 3 ), the large bandgap tunability of group III-nitrides also allows the absorption or cut-off wavelength to be engineered by simply changing the alloy composition, an easy tailoring for demanding applications that require high signal-to-noise ratios (SNR) and spectrum se- lectivity. Apart from that, high thermal and chemical stabilities of group III-nitride material system stands out in harsh environments, compared to conventional silicon-based detectors, which have limited operating temperature range and require extra protective packaging [470][471][472][473] . In addition, siliconbased photodetectors typically have low photoresponsivity in the UV regime of operation due to low penetration depth of UV-wavelength photons in silicon [474] .…”

Ultra‐High and Fast Ultraviolet Response Photodetectors Based on Lateral Porous GaN/Ag Nanowires Composite Nanostructure

“…UV photodetectors have drawn lots of attention in recent years because of many potential applications, such as flame detection, environmental monitoring, missile plume detection, and space communication,1,2 where the high sensitivity with a fast response UV photodetectors are strongly desired. As the representative of the direct wide bandgap semiconductors, GaN is a good candidate for UV photodetectors because of its intrinsic UV absorption window, high electron saturation drift velocity, good stability, relative mature epitaxial growth technology, etc 3,4. Till now, many kinds of GaN‐based photodetectors have been proposed 5–8.…”