A Novel Ultraviolet Photodetector With High Responsivity and Low Operating Voltage Based on Hybrid Si/SiC Technology

In this letter, we demonstrate a novel ultraviolet (UV) photodetector with extremely high responsivity under low operating voltage of 1 V. A Silicon/silicon carbide (Si/SiC) hybrid substrate and fabrication process are developed to monolithically integrate a SiC photodetector with a Si MOSFET. The SiC photodetector provides excellent UV selectivity, and its output signal is further amplified through the integrated silicon MOSFET. The UV photodetector exhibits a responsivity up to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4.63\times 10^{{5}}$ </tex-math></inline-formula> A/W at a wavelength of 260 nm under a 1-V drain voltage, which is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3.08\times 10^{{7}}$ </tex-math></inline-formula> times enhanced compared to SiC metal-semiconductor–metal (MSM) photodetector. Additionally, the detector exhibits excellent response speed with rise and fall times of 29 and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$17~\mu $ </tex-math></inline-formula> s, respectively, under a light intensity of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4~\mu $ </tex-math></inline-formula> W/cm2. Moreover, the detectivity is optimized by adjusting the gate voltage and a record high value of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4.18\times 10^{{16}}$ </tex-math></inline-formula> Jones is achieved.