Droplet epitaxy of 3D zinc-blende GaN islands on a 2D van der Waals SiN structure

• DOI: 10.1016/j.apsusc.2024.159595
• Publication Date: 2024-02-06T18:03:36Z
• Authors: Y.E. Maidebura; V.G. Mansurov; T.V. Malin; A.N. Smirnov; K.S. Zhuravlev; B. Pecz

GaN quantum dots (QDs) have enormous potential for applications in science and technology, but their optimal use requires precise control of parameters such as density, size and monodispersity. To address this issue, we use the conventional method of forming QDs – droplet epitaxy, on the unconventional surface – graphene-like SiN formed on Si(1 1 1). When droplet epitaxy is used on conventional surfaces such as Si(0 0 1), Si(1 1 1), SiO2, or Al (Ga)N, there is material exchange between droplets during crystallization, which makes it difficult to control parameters and form monodisperse QDs. The atomically smooth surface of g-SiN with weak van der Waals in- teractions allowed us to nucleate Ga droplets in a controlled manner. Meanwhile, amorphization of the g-SiN layer during the droplet crystallization process allowed us to suppress material exchange between the droplets, resulting in QDs with a narrow size distribution. Structural analysis revealed unstrained QDs with a zinc-blende structure due to weak bonding between the QDs and the g-SiN layer. Overall, the proposed method provides a way to grow unstrained and monodisperse ZB-GaN QDs on an accessible substrate with control over their density and size, which is particularly important for the widespread application of GaN QDs.