Formation of voids in selective area growth of InN nanorods in SiN_x on GaN templates

Abstract

Experimental data and a supporting model are presented for the formation of voids in InN nanorods grown by selective area hydride vapor phase epitaxy (HVPE) on patterned GaN/c-Al2O3 templates. It is shown that these voids shape, due to a high lattice mismatch between InN and GaN materials, starts from the base and extends up to a half of the total length of the nanorods. When the effect of the mismatch between substrate and nanorods becomes weaker, the hollow nanotubes close up at the top and further growth proceeds in the standard nanowire geometry without voids. This effect is observed within a wide range of growth conditions during the InN synthesis and must be taken into account for controlling the final structure of InN nanorods for different device applications.

Formation of Hexagonal Ge Stripes on the Side Facets of AlGaAs Nanowires: Implications for Near-Infrared Detectors

“…The energetically preferred shape of the Ge stripe is now given by the minimum of f at a given volume v , similar to refs and . In the wetting case α < 0, f decreases monotonically with x , yielding the conformal growth of a continuum shell around the NW with x = R regardless of v .…”

Modeling the Shape Evolution of Selective Area Grown Zn3P2 Nanoislands

“…We now examine the extrema of the surface energy as a function of B and L 1 at a fixed length L , which is similar to the approach of refs – . Differentiating f with respect to B and L 1 , we obtain and ∂ 2 f /∂ B 2 = −2­(1 – a ) and ∂ 2 f /∂ L 1 2 = 2­(1 – b ).…”

Criterion for the growth selectivity of III-V and III-N nanowires on masked substrates

“…One-dimensional geometry and a small area of contact of different materials provide an opportunity to grow III−V and III-N nanowires (NWs) on silicon substrates without the emergence of mismatch dislocations and form heterostructures in strongly mismatched material systems [1][2][3]. The growth of III−V and III-N NWs by selective area epitaxy (SAE) on masked substrates with regular arrays of pinholes [4][5][6][7][8][9][10][11] allows one to synthesize NW ensembles uniform in size with exactly determined positioning of NWs and distances between them. The SAE technique is also used to synthesize nanomembranes [12,13] and nanoislands [14] of various geometry.…”

“…These structures hold much promise for application in nanophotonics and nanoelectronics with an option for integration into silicon electronic technology. The selectivity of SAE of NWs without growth catalyst droplets in arrays of pinholes in a SiO x mask on a Si(111) substrate [4][5][6][7][8][9][10][11] is ensured by (1) nucleation of NWs within pinholes on the Si surface;…”