Large enhancement of sub-band-gap light absorption of sulfur hyperdoped silicon by surface dome structures

摘要

Sulfur hyperdoped silicon was usually prepared by sulfur ion implantation and nanosecond laser annealing. It has a smooth surface and a low sub-band-gap absorption of 30%. Here we report that the surface of silicon wafer was chemically textured before it was treated by the above two processes, which greatly enhanced the light absorption of the hyperdoped silicon from 30% to 70% in sub-band-gap wavelength and from 65% to 80% in visible wavelength for the antireflection characteristics of the formed dome structures. Consequently, the surface texture process will be a necessary step for device development that is based on sulfur hyperdoped silicon materials.