Broadband 400-2400 nm Ge heterostructure nanowire photodetector fabricated by three-dimensional Ge condensation technique

Abstract

A 2.7% tensile strained Ge/SiGe heterostructure nanowire (NW) is in-situ fabricated by a three-dimensional Ge condensation method. The NW metal-semiconductor-metal (MSM) photodetector demonstrates an ultra-broadband detection wavelength of 400-2400 nm, showing a high responsivity of >3.46×10² A/W with a photocurrent gain of >4.32×10² at 1550 nm under -2 V. A high normalized photocurrent to dark current ratio (NPDR) of 1.88×10¹¹ W^-1 at 1550 nm under -1 V is achieved. The fully complementary metal-oxide-semiconductor (CMOS) compatible, simple and scalable process suggest that the Ge heterostructure NW is promising for low cost, high performance near-infrared or short wavelength infrared focal plane array applications.