Growth of oriented polycrystalline α-HgI2 films by ultrasonic-wave-assisted physical vapor deposition

Abstract Polycrystalline α-HgI 2 thick films have been grown on ITO-coated glass substrates using ultrasonic-wave-assisted vapor phase deposition (UWAVPD) with the different source temperatures and ultrasonic frequencies. The influence of the assisted ultrasonic wave and source temperature on the structural and electrical properties of the polycrystalline α-HgI 2 films is investigated. It is found that the assisted ultrasonic wave plays an important role in the improvement of the structural and electrical properties. An uniformly oriented polycrystalline α-HgI 2 film with clear facets and narrow size distribution can be obtained at the source temperature of 80 °C under the assistance of 59 KHz ultrasonic frequency with the ultrasonic power of 200 W, which has the lowest value of ρ =2.2×10 12  Ω cm for E -field parallel to c -axis, approaching to that of high quality α-HgI 2 single crystals (4.0×10 12  Ω cm).