Synthesis of Colloidal GaN and AlN Nanocrystals in Biphasic Molten Salt/Organic Solvent Mixtures under High-Pressure Ammonia

Abstract

Group III nitrides are of great technological importance for electronic devices. These materials have been widely manufactured via high-temperature methods such as physical vapor transport (PVT), chemical vapor deposition (CVD), and hydride vapor phase epitaxy (HVPE). The preparation of group III nitrides by colloidal synthesis methods would provide significant advantages in the form of optical tunability via size and shape control and enable cost reductions through scalable solution-based device integration. Solution syntheses of III-nitride nanocrystals, however, have been scarce, and the quality of the synthesized products has been unsatisfactory for practical use. Here, we report that incorporating a molten salt phase in solution synthesis can provide a viable option for producing crystalline III-nitride nanomaterials. Crystalline GaN and AlN nanomaterials can be grown in a biphasic molten-salt/organic-solvent mixture under an ammonia atmosphere at moderate temperatures (less than 300 °C) and stabilized under ambient conditions by postsynthetic treatment with organic surface ligands. We suggest that microscopic reversibility of monomer attachment, which is essential for crystalline growth, can be achieved in molten salt during the nucleation and the growth of the III-nitride nanocrystals. We also show that increased ammonia pressure increases the size of the GaN nanocrystals produced. This work demonstrates that use of molten salt and high-pressure reactants significantly expands the chemical scope of solution synthesis of inorganic nanomaterials.

Exploring synthesis and applications of green nanoparticles and the role of nanotechnology in wastewater treatment

“…Nanomaterials are made using this automated technique. During this process, the components are ground in a closed container [50] . When grinding, tiny glass, ceramic, and stainless steel pebbles create sheer stress.…”

Design Rules for Obtaining Narrow Luminescence from Semiconductors Made in Solution

“…Progress has been made with the colloidal synthesis of GaN nanocrystals and nanorods; however, band-edge emission still remains elusive in solution-derived III−N materials. 321 Promisingly, the success of nitride-based visible and UV emitters synthesized from gas-phase CVD and MBE growth suggests that these materials have considerable potential. Based on this, there remain many opportunities for synthesis science developments to realize generalized preparation of visible III−V emitters in solution.…”

“…In 1– x Ga x N represents a final candidate for visible-emitting III–V colloidal nanocrystals; however, to date, synthetic methods to synthesize these materials have not been developed. Progress has been made with the colloidal synthesis of GaN nanocrystals and nanorods; however, band-edge emission still remains elusive in solution-derived III–N materials . Promisingly, the success of nitride-based visible and UV emitters synthesized from gas-phase CVD and MBE growth suggests that these materials have considerable potential.…”

Design rules for obtaining narrow luminescence from semiconductors made in solution

“…Progress has been made with the colloidal synthesis of GaN nanocrystals and nanorods however band edge emission still remains elusive in solution derived III-N materials. 308 However, the success of nitride based visible and UV emitters based on gas phase CVD and MBE growth suggest these materials have considerable promise. Based this this, there remain many opportunities for synthesis science developments to realize generalized preparation of potential visible III-V emitters in solution.…”