Catalytic growth of group III-nitride nanowires and nanostructures by metalorganic chemical vapor deposition

Abstract

We report flexible synthesis of group III–nitride nanowires and nanostructures by metalorganic chemical vapor deposition (MOCVD) via a catalytic vapor-liquid-solid (VLS) growth mechanism. Supersaturation and surface stoichiometry strongly influence the stability of liquid droplets and growth selectivity. To facilitate and sustain the VLS growth, indium catalyst is introduced based on thermodynamic consideration. The employment of mesoporous molecular sieves (MCM-41) helps to prevent the coalescence of catalyst droplets and to promote nucleation statistics. Both GaN and AlN nanowires have been synthesized using MOCVD. Three-dimensional AlN∕GaN trunk-branch nanostructures are reported to illustrate the versatility of incorporating the VLS mechanism into MOCVD process.

Growth of AlN nanowires by metal organic chemical vapour deposition

“…GaN and InN nanowires have been prepared by various techniques including plasma-assisted molecular beam epitaxy [5], laser ablation [6], metal organic chemical vapour deposition [7] and reaction of NH 3 with Ga [3,4] (In [8]) powder, Ga/GaN [2] or Ga/Ga 2 O 3 [9] (In/In 2 O 3 [10]) mixtures. In contrary, little is reported on the preparation of AlN nanowires [11,12].…”

AlN nanowires: synthesis, physical properties, and nanoelectronics applications

“…Also, it was found that the nanowires had a uniform single-crystalline core surrounded by an amorphous coating. On the other hand, by employing In as a catalyst to assist the VLS growth, Su et al [41] had synthesized AlN nanowires through metal-organic chemical vapor deposition. From their observations, the group concluded that the stability of the liquid droplets and the selectivity in the VLS growth process relied very much on the supersaturation level and surface stoichiometry.…”

“…Various fabrication methods have been employed to synthesize these nanowires and they may be classified into four main classes: (1) template-confined method [16,[31][32][33], (2) direct current (DC) arc discharge method [34][35][36][37][38], (3) catalyst-assisted vapor-liquid-solid (VLS) growth method [39][40][41][42][43][44][45][46], and (4) catalyst-free vapor-solid (VS) growth method [47][48][49][50][51][52][53][54][55][56][57][58][59][60][61][62][63]. Although significant progress in the synthesis of AlN nanowires has been achieved lately, some challenges remain and are expected to be overcome in the near future.…”

Epitaxial growth of aligned GaN nanowires and nanobridges

“…Synthesis of wide bandgap GaN NWs has been reported on a variety of substrates, including alumina [3,4], quartz [5], silicon dioxide [6], silicon (111) [7], and c-face sapphire; morphology of haystack-like, random-oriented GaN NWs are commonly observed. These NWs are typically processed into devices through solution sonication and dispersion unto target wafers before electrically contacted by metallization.…”