Deep UV Sensors Enabling Solar-Blind Flame Detectors for Large-Area Applications

Large-area compatible, solar-blind deep-ultraviolet sensors based on active pixels are demonstrated with CMOS amplifiers based on poly-Si thin-film transistors and Ga
₂
O
₃
thin-film photoresistors. The active pixel configuration sensor enables approximately 40X higher responsivity compared to a discrete sensor, and the CMOS inverter amplifier exhibits a gain of 210 V/V. The Ga
₂
O
₃
-based sensors were integrated on the same substrate depositing the films using magnetron sputtering at room temperature, ensuring its compatibility with large-area applications. The responsivity of discrete Ga
₂
O
₃
sensors was evaluated at different wavelengths in the deep-ultraviolet and visible ranges, and showed a maximum responsivity of 51 A/W for a wavelength of 232 nm, with a deep-ultraviolet to visible light rejection ratio of approximately 10
²
. The active pixel sensor was implemented as flame detector resulting in an output voltage signal of up to 2 V when the system was exposed to a flame under regular background illumination conditions.