Low Temperature Growth of In(2)O(3)and InN Nanocrystals on Si(111) via Chemical Vapour Deposition Based on the Sublimation of NH(4)Cl in In

Indium oxide (In(2)O(3)) nanocrystals (NCs) have been obtained via atmospheric pressure, chemical vapour deposition (APCVD) on Si(111) via the direct oxidation of In with Ar:10% O(2)at 1000 °C but also at temperatures as low as 500 °C by the sublimation of ammonium chloride (NH(4)Cl) which is incorporated into the In under a gas flow of nitrogen (N(2)). Similarly InN NCs have also been obtained using sublimation of NH(4)Cl in a gas flow of NH(3). During oxidation of In under a flow of O(2)the transfer of In into the gas stream is inhibited by the formation of In(2)O(3)around the In powder which breaks up only at high temperatures, i.e.T > 900 °C, thereby releasing In into the gas stream which can then react with O(2)leading to a high yield formation of isolated 500 nm In(2)O(3)octahedrons but also chains of these nanostructures. No such NCs were obtained by direct oxidation forT(G) < 900 °C. The incorporation of NH(4)Cl in the In leads to the sublimation of NH(4)Cl into NH(3)and HCl at around 338 °C which in turn produces an efficient dispersion and transfer of the whole In into the gas stream of N(2)where it reacts with HCl forming primarily InCl. The latter adsorbs onto the Si(111) where it reacts with H(2)O and O(2)leading to the formation of In(2)O(3)nanopyramids on Si(111). The rest of the InCl is carried downstream, where it solidifies at lower temperatures, and rapidly breaks down into metallic In upon exposure to H(2)O in the air. Upon carrying out the reaction of In with NH(4)Cl at 600 °C under NH(3)as opposed to N(2), we obtain InN nanoparticles on Si(111) with an average diameter of 300 nm.