High infrared responsivity of silicon photodetector with titanium-hyperdoping

Abstract

Silicon (Si) photodetectors have advantages of low cost, convenient preparation, and high integration. However, limited by the indirect bandgap of 1.12 eV, Si photodetectors cannot perform at the wavelength beyond 1100 nm. It is attractive to extend the response wavelength of Si-based photodetectors for the optoelectronics application in recent years. In this article, we have successfully prepared a high-performance photoconductive detector based on titanium-hyperdoped Si (Si:Ti). The Si:Ti material shows an enhanced infrared absorption primarily attributed to the sub-bandgap photo excitation assisted by titanium (Ti)-induced energy states with an average energy level of Ev + 0.23 eV. Moreover, the detector exhibits a high responsivity of 200 mA·W-1 under 1550nm light at 5 V bias, which is higher than previously reported transition metals hyperdoped silicon detectors. These results are helpful for the development of infrared hyperdoped silicon photodetectors in the field of optoelectronics.

Long infrared detector based on Se-hyperdoped black silicon

“…Similarly, the b-Si hyperdoped with nitrogen achieves a sensitivity of 5.3 mA W −1 at 1.31 µm under a reverse voltage of 10 V [51]. Furthermore, Additionally, titanium-hyperdoped Si achieves an R p of 200 mA W −1 at 1.55 µm under a 5 V reverse voltage [52]. Remarkably, the hybridized graphene/Te-Si photodetector exhibits a significantly higher R p of 100 A W −1 at 1.55 µm [43].…”

The Mechanism Behind the Annealing‐Induced Reduction of Infrared Absorption in Zinc‐Hyperdoped Silicon

“…Similar results on Ag and Ti femtosecond laser‐hyperdoped Si samples have also been reported before. [ 25,26 ] This is because the enhancement of bandgap absorption mainly originates from the antireflection effect of surface microstructures. However, for the sub‐bandgap near‐infrared light, the absorption of the Si:Zn samples significantly decreases after conventional annealing, and this attenuation becomes more pronounced with the increasing temperature of annealing.…”