Hydride vapor phase epitaxy (HVPE) of InN using In metal, Cl-2 and NH3 as source, materials and N-2 carrier gas was investigated on sapphire (0 0 0 1) substrates. A thermodynamic analysis of the reaction between In metaland Cl-2 gas in the source zone of the HVPE system revealed that the equilibrium partial pressure of InCl3 increased significantly with decreasing source zone temperature, while that of InCl remained almost constant. At a substrate temperature of 500 degrees C, appreciable growth, of InN occurred by decreasing the source zone temperature to 450 degrees C. This means that,InN growth occurs by the reaction between, InCl3 and NH3. With an optimum surface nitridation time of the sapphire substrate prior to InN growth, c-axis oriented single-crystal line layers of InN were obtained. Cathodoluminescence (CL) spectrum measured at room temperature showed a strong peak at 0.75 eV. (c) 2006 Elsevier B.V. All rights reserved.