We demonstrated an ultra-high-performance and self-powered β-Ga2O3 thin film solar-blind photodetector fabricated on cost-effective Si substrate using a high-temperature seed layer (HSL). The polycrystalline β-Ga2O3 thin film deposited with HSL shows high-performance in the solar-blind region in comparison to the amorphous Ga2O3 thin film deposited without HSL.
The zero-bias digitizing sensor prototype with HSL produces a digitized output bit with deep UV (DUV) light which exhibits high on/off (I254nm/Idark) ratio >103, a record low dark current of 1.43 pA, and high stability and reproducibility over 100 cycles even after >2100 hrs. The photodetector shows minimum persistent photoconductivity and fast response in msec.
The photodetector yield the responsivity of 96.13 A W-1 with external quantum efficiency (EQE) of 4.76×104 at 5 V for 250 nm monochromatic light. The photodetector shows a high response to an even rare weak signal of DUV (44 nW/cm2).
These values are the highest reported till date for planner β-Ga2O3 thin film based photodetector despite the use of the cost-effective substrate. The asymmetric I-V curve indicates a dissimilar Schottky barrier height (SBHs) at two ends of MSM photodetector and discussed as the main reason for the high response even at zero bias.
This work provides the guideline to develop β-Ga2O3 based cost-effective, self-powered, high-performance and fast DUV photodetector which possesses the high potential for next generation practical solar-blind photodetector application.
Arora, K., Goel, N., Kumar, M. and Kumar, M., 2018. Ultra-high-performance of Self-Powered β-Ga2O3 Thin Film Solar-blind Photodetector Grown on Cost-Effective Si Substrate using High-Temperature Seed Layer. ACS Photonics.
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