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

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.