Rotated domains in selective area epitaxy grown Zn₃P₂: formation mechanism and functionality

Abstract

Growth process for Zn3P2 nanowires grown on InP at different angles by SAE and formation of rotated domains at (100) and (101) facets.

Showcasing the optical properties of monocrystalline zinc phosphide thin films as an earth-abundant photovoltaic absorber

“…It has recently been shown that rotated crystallites with interfaces free of dangling bonds can be formed during growth. 50 DFT calculations have shown that the electronic bandgap at these interfaces is significantly decreased compared to the bulk, on the order of 0.1 eV smaller, and new localized acceptor levels are formed. The existence of these 2D defects also appears to have near to no additional energetical cost compared to their absence, though their dependence on temperature is still unknown.…”

Nanoscale Growth Initiation as a Pathway to Improve the Earth-Abundant Absorber Zinc Phosphide

“…The morphology of the nanostructure is a function of the shape of the hole. Nanopyramids are the result for circular holes, while nanowires, or even nanowire networks, are achieved from elongated slits as shown in Figure . − However, these shapes are only observed after a couple of intermediate stages. The intermediate morphology as zinc phosphide outgrows the hole depends on the relative surface energies of the dominating facets, namely, (001), (112), and (101).…”

“…The interface between the indium phosphide substrate and zinc phosphide was investigated using HR-TEM and AC HAADF-STEM of FIB lamellae and did not include any misfit dislocations. , The interface roughness observed was due to non-optimized pattern etching. The epitaxial relationship observed was [001] Zn 3 P 2 /[001] InP , making the vertical growth direction of zinc phosphide the c -axis ([001] Zn 3 P 2 ).…”

“…The epitaxial relationship observed was [001] Zn 3 P 2 /[001] InP , making the vertical growth direction of zinc phosphide the c -axis ([001] Zn 3 P 2 ). This combination results in the minimum strain in the zinc phosphide . Most of the epitaxial strain is relaxed by the time the structure starts to grow out of the hole in the mask.…”

“…These domains are related to when the growth front shifts from a (001) Zn 3 P 2 to a (101) Zn 3 P 2 surface and is characterized by a 120° rotation around the (101) Zn 3 P 2 plane. , The rotated defects were mainly observed in the edges when the zinc phosphide starts to overgrow the mask. However, they could also be observed within the nanowires when {101} Zn 3 P 2 surfaces randomly form during early stages of the growth and provide nucleation sites for these domains . As they continued to grow, they also form extended (100) Zn 3 P 2 //(112) Zn 3 P 2 interfaces.…”