Tantalum nitride nanotube photoanodes: establishing a beneficial   back-contact by lift-off and transfer to titanium nitride layer
  In this work we introduce the use of TiN/Ti2 N layers as a back contact for lifted-off membranes of anodic Ta3N5 nanotube layers. In photoelectrochemical H2 generation experiments under simulated AM 1.5G light, shift of the onset potential for anodic photocurrents to lower potentials is observed, as well as a higher magnitude of the photocurrents compared to conventional Ta3N5 nanotubes (~ 0.5 V RHE ). We ascribe this beneficial effect to the improved conductive properties of the TiNx -based back contact layer that enables a facilitated electron-transport for tantalum-nitride based materials to the conductive substrate. 
Lei Wang, Anca Mazare, Imgon Hwang, Patrik Schmuki
cond-mat.mtrl-sci