Analysis of nano-grating-assisted light absorption enhancement in metal-semiconductor-metal photodetectors patterned using focused ion-beam lithography

作者：Das Narottam^*; Karar Ayman; Vasiliev Mikhail; Tan Chee Leong; Alameh Kamal; Lee Yong Tak

来源：Optics Communications, 2011, 284(6): 1694-1700.

DOI：10.1016/j.optcom.2010.11.065

• MSM photodetectors
• Surface plasmons
• Plasmonic nano-gratings
• Absorption enhancement
• FDTD analysis

We present finite-difference time-domain (FDTD) analysis results of light absorption enhancement factor dependence on the profile shape of nano-gratings etched into the surfaces of metal-semiconductor-metal photodetector (MSM-PD) structures. The MSM-PDs patterned by nano-gratings are optimized geometrically. improving the light absorption near the design wavelength through plasmon-assisted electric field concentration effects. FDTD simulation results show about 50 times light absorption enhancement prediction for 850 nm light due to improved optical signal propagation through the nano-gratings in comparison with the conventional MSM-PD designs employing only a subwavelength aperture. We also report on the nano-grating profile shapes obtained typically in our experiments using focused ion-beam lithography and discuss the dependency of light absorption enhancement on the geometric parameters of nano-gratings inscribed into MSM-PDs.

• 出版日期2011-3-15