Effect of Polytetrafluoroethylene additive on low-temperature synthesis of InN crystals via reaction of LiInO2 and NaNH2

We examined the effect of polymer polytetrafluoroethylene ( PTFE) additive on the growth of InN crystals by the nitridation of LiInO2 in NaNH2 flux at 240 degrees C. LiInO2 and NaNH2 powder were heated with/without PTFE pieces in a steel crucible located inside the PTFE-lined autoclave. The additive of PTFE pieces enhanced the decomposition of LiInO2 with the mass loss of these pieces and progressed the formation of InN and In(OH)(3) byproducts. SEM and TEM images of the products using PTFE additives showed the hexagonal InN crystals of similar to 1 mu m in size, and the optical bandgap of synthesized InN was estimated as similar to 2.03 eV. We presume that fluorine in PTFE additive subtracts Li from LiInO2 and enhances the growth of InN crystals. (C)2014 The Ceramic Society of Japan. All rights reserved.