Impact of deposition pressure and two-step growth technique on the photoresponsivity enhancement of polycrystalline BaSi2 films formed by sputtering

Abstract

We investigate the influence of deposition pressure in the range 0.25-1.0 Pa on the photoresponsivity of 200 nm thick BaSi2 films grown by sputtering at 600 °C. BaSi2 films formed at 0.8 Pa exhibit a high photoresponsivity. The deposited Ba-to-Si atomic ratio depends significantly on the sputtering pressure. That's why the pressure influences the photoresponsivity. BaSi2 films grown by a two-step growth technique show much higher photoresponsivity almost equivalent to those grown by molecular beam epitaxy. The photoresponsivity reaches 0.75 A W-1 at 2.0 eV at a bias voltage of 0.5 V applied between the top and bottom electrode.