Group IV THz large area emitter based on GeSn alloy

Abstract

THz photoconductive emitters based on III–V materials have demonstrated excellent THz radiation properties, enabling many unique applications. However, the incompatibility with the complementary-metal-oxide-semiconductor (CMOS) foundry fabrication process and the challenging growth condition hampers THz photoconductive emitters from large-scale production. To address this limitation, we proposed the GeSn alloy as the photoconductive material candidate through the CMOS-compatible epitaxy instrument. The GeSn photoconductor features a 518 cm2/V-s mobility and a 7187 cm–1 absorption coefficient at the wavelength of 1560 nm, resulting in sufficiently ultrafast photocurrent generation for THz radiation. As a result, the GeSn THz emitter provides over a bandwidth of 2 THz and a 40 dB signal-to-noise ratio, which shows its potential in realizing mass-producible, cost-effective THz integrated systems with CMOS technology.