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.

Cadmium sulfide thin film transistors were demonstrated as the n-type device for use in flexible electronics. CdS thin films were deposited by chemical bath deposition ( ) on either 100 nm or as the gate dielectrics. Common gate transistors with channel lengths of were fabricated with source and drain aluminum top contacts defined using a shadow mask process. No thermal annealing was performed throughout the device process. X-ray diffraction results clearly show the hexagonal crystalline phase of CdS. The electrical performance of -based thin film transistors shows a field effect mobility and threshold voltage of and 2 V, respectively. Improvement in carrier mobility is associated with better nucleation and growth of CdS films deposited on .

In recent years $\beta $ -Ga ₂ O ₃ thin films and crystals have gained attention as excellent candidates for transparent and high-power applications due to its wide band gap (4.6 – 4.9 eV) and large breakdown field (~8 mV/cm). However, $\beta $ -Ga ₂ O ₃ single crystals and highly crystalline $\beta $ -Ga ₂ O ₃ thin films require high temperature, long processing times and, often, expensive tools that limit integration with other technologies. Amorphous Ga ₂ O ₃ has not been studied as intensely as $\beta $ -Ga ₂ O ₃ and mostly metal-semiconductor-metal (MSM) structures and diodes using this material have been reported. In this paper, we discuss a simple and economical method to fabricate thin film transistors (TFTs) based on un-doped amorphous Ga ₂ O ₃ thin films deposited at room temperature by magnetron sputtering. Control of the Ga ₂ O ₃ thin films resistivity over a wide range is demonstrated by controlling the deposition power and pressure. The TFTs show a threshold voltage ( $\text{V}_{{\mathrm {T}}}$ ) of 0.92 V, saturation mobility ( $\mu _{{\mathrm {sat}}}$ ) of 0.511 cm ² / $\text{V}\cdot \text{s}$ and subthreshold slope (SS) of 83.62 mV/dec. More importantly, these devices have been evaluated as phototransistors, which has not been intensely studied yet. The phototransistors tested under DUV radiation exhibited a rejection ratio UV-Visible of 10 ³ and responsivity of $10^{2}\text{A}$ /W ( $\text{V}_{{\mathrm {G}}} =0$ V) and 10 ⁴ A/W ( $\text{V}_{{\mathrm {G}}} =6$ V), gain of 10 ³ , specific detectivity of 10 ¹⁵ Jones and a photosensitivity of 10 ⁷ .