Optical switching and photoluminescence in erbium implanted vanadium dioxide thin films

Vanadium dioxide (VO2) undergoes an insulator-metal transition (IMT) that involves drastic changes in its electrical and optical properties at relatively low critical temperature Tc ≈ 67°C [1]. The switching speed when triggered by an optical impulse is incredibly fast, within a femtosecond timescale [2]. Erbium (Er3+) with a stimulated emission at the standard telecommunication wave-length of 1535nm has been used extensively in fiber-optic communication systems [3]. The combination of VO2 and Er3+ could make an ultrafast optical switch that is capable of simultaneous signal amplification. In this work, we investigated the possibilities of making such a device, both theoretically and experimentally. Our experimental methods involve temperature-driven optical switching tests and photoluminescence (PL) spectroscopy on Er3+ implanted VO2 thin films. The observations of the IMT of VO2 and the PL of Er3+ in the thin films would be vital in determining whether the VO2:Er system would work as an optical switch and amplifier. A range of implantation and post-annealing schemes were explored in an attempt to find the optimal processing conditions that would maximize the qualities of the optical switching and PL.