Visible Light-Driven p-Type Semiconductor Gas Sensors Based on CaFe2O4 Nanoparticles. - Qomaruddin Qomaruddin; Olga Casals; Andris Sutka; Tony Granz; Andreas Waag; Hutomo Suryo Wasisto; Joan Daniel Prades; Cristian Fàbrega (Sensors, 2020)