A new preparation process of GaN: solvothermal synthesis.

GaN, a large band-gap semiconductor (3.49 eV), is a very promising material concerning the optoelectronic and microelectronic areas, mainly due to the value of the band gap and also to its high chemical and thermal stability. Most of the work concerning this nitride implies the formation of thin films by various techniques of epitaxy. The solvothermal synthesis is a new route to obtain GaN. This process is conducted in a nitriding solvent in the supercritical state (T > T-c and P > P-c) or close to it. In such conditions, the diffusion of the chemical species is enhanced. Microcrystallites of GaN of good chemical purity have been obtained by this process. The obtained microcrystallites have been characterised by several techniques: X ray diffraction and scanning electron microscopy. (C) 1999 Academie des sciences/Editions scientifiques et medicales Elsevier SAS.