Technical Proceedings of the 2007 Clean Technology Conference and Trade Show

Clean Technology 2007

Chapter 2: Energy Applications of Nanotechnology

V. Rawat and T.D. Sands
Purdue University, US
63 - 66
thermionic, energy conversion, nitride
This work deals with investigation of metal/semiconductor nitrides for potential application as solid state thermionic energy converters. TiN/GaN multilayers were deposited on Sapphire and MgO substrate using reactive pulsed laser deposition. This is the first time, to the best of authors’ knowledge, that crystalline and textured metal-semiconductor multilayers have been fabricated in any materials system. The crystallographic analysis of the multilayers was done using high resolution X-Ray diffraction and cross-sectional TEM which revealed that despite the different in crystal structures of GaN(wurtzite) and TiN(rocksalt), the presence of texture within the layers helped in stabilization of the multilayer structure. The in-plane electrical parameters of the multilayers, including in-plane Seebeck coefficient, as a function of multilayer period have been measured. The thermal conductivity of the multilayers have also been measured and it has shown dramatic decrease in thermal conductivity of the multilayer from the bulk thermal conductivity values its two components. The materials, thermal and electrical behavior of these novel multilayers make them suitable for use as efficient thermionic energy converters.
TiN/GaN- Metal/Semiconductor Multilayers for Thermionic Energy Conversion Devices