Facile Fabrication of Ta4N5 Nanorod Arrays Using Sputtering and Their Photo-related Activities

Abstract

Abstract Ta4N5 is N-rich thermodynamically stable phase however Ta4N5 did not obtain much attention comparing with Ta3N5 especially using sputtering From our research the band gap of Ta4N5 is approximate 2 5 eV that can effectively utilize the visible light up to 500 nm which is promising for photocatalysis In this research reactive sputtering was used to directly grow Ta4N5 nanorod arrays on a FTO substrate for the photo-related applications Well separated and polycrystalline Ta4N5 nanorod arrays were obtained by tuning the parameters of the Ar/N2 ratio the working distances between the gun and the substrate the sputtering pressures and the DC power Various characterization tools such as XRD SEM TEM and UV-VIS were used to study the properties The photodegradation performance was studied Both in-situ 600 ?C and 550 ?C samples showed a considerable improvement under the environment at pH = 10 approximately 2 times faster than that measured at pH = 7 The photoelectrochemical current for the in-situ 600 ?C samples was measured approximate 4 ?A/cm2 under visible light illumination at the constant bias supply at 0 5 V The IPCE of the in-situ 600?C sample was found approximately 3% and the IPCE variation trend as a function of wavelength was found in a good agreement with the UV-VIS absorption spectrum Ta4N5 nanorods showed excellent stability after a cycling test consisting of three runs and seven cycles for each run The future works for this research include pursuing the followings: much better separation of Ta4N5 nanorods with excellent crystallinity Ta3N5 nanorod structures various cation dopings and water splitting to obtain H2 fuels

Date of Award	2014 Aug 6
Original language	English
Supervisor	Kao-Shuo Chang (Supervisor)