Lasing in Zn-doped GaAs nanowires on an iron film

Abstract

In this work, we demonstrate optically pumped lasing in highly Zn-doped GaAs nanowires lying on an iron film. The conically shaped nanowires are first covered with an 8 nm-thick Al2O3 film to prevent atmospheric oxidation and mitigate band-bending effects. Multimode and single-mode lasing have been observed for nanowires with a length greater or smaller than 2 µm, respectively. Finite difference time domain calculations reveal a weak electric field enhancement in the Al2O3 layer at the nanowire/iron film interface for the lasing modes. The high Zn acceptor concentration in the nanowires provides enhanced radiative efficiency and enables lasing on the iron film despite plasmonic losses. Our results open avenues for integrating nanowire lasers on ferromagnetic substrates to achieve new functionalities, such as magnetic field-induced modulation.