Exploring the Size Limitations of Wurtzite III–V Film Growth

Abstract

Metastable crystal phases of abundant semiconductors such as III−Vs, Si, or Ge comprise enormous potential to address current limitations in green light-emitting electrical diodes (LEDs) and group IV photonics. At the same time, these nonconventional polytypes benefit from the chemical similarity to their stable counterparts, which enables the reuse of established processing technology. One of the main challenges is the very limited availability and the small crystal sizes that have been obtained so far. In this work, we explore the limitations of wurtzite (WZ) film epitaxy on the example of InP. We develop a novel method to switch and maintain a metastable phase during a metal− organic vapor phase epitaxy process based on epitaxial lateral overgrowth and compare it with standard selective area epitaxy techniques. We achieve unprecedented large WZ layer dimensions exceeding 100 μm 2 and prove their phase purity both by optical as well as structural characterization. On the basis of our observations, we further develop a nucleation-based model and argue on a fundamental size limitation of WZ film growth. Our findings may pave the way toward crystal phase engineered LEDs for highly efficient lighting and display applications.

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

“…16,23–25,29–32 The small interface area helps to limit the formation of interface related defects, and the shape of the nanostructure can be controlled by the geometry of the openings. 16,29,33,34 While this helps minimise the interface related defects, there are other sources of defects in Zn 3 P 2 . 35–38 Various defect levels in the bandgap have been experimentally probed by various groups previously, but very few have been able to describe the exact origins.…”

Review of Highly Mismatched III-V Heteroepitaxy Growth on (001) Silicon

“…Figure 2 c is the stacking faults that can occur during the III-V growth. If the stacking sequence changes in every layer, a zinc-blende (ZB) ABC stacking can be switched to a Wurtzite (WZ) ABAB stacking [ 35 , 36 ], which can impact the optical band gap since some semiconductors exhibit different band gaps for different crystal structures [ 37 ] or even change the band gap from indirect to direct or vice versa [ 38 , 39 ]. The heteroepitaxial growth of mismatched III/V on Si introduces additional challenges; hence, the mechanisms of challenges and the defect will be discussed below.…”

Understanding Shape Evolution and Phase Transition in InP Nanostructures Grown by Selective Area Epitaxy

“…[36][37][38] Furthermore, SAE of 2D and 3D nanostructures may have different mechanism, as reported in the formation of twin-free GaAs nanosheets [21] and large size pure WZ InP nanomembranes. [39] The limited studies associated with the specific nanostructure geometry (e.g., nanowire), crystal phase and substrate orientation lead to the lack of a unified model or understanding for SAE of III-V nanostructures, which seriously impedes the advances in the growth of nanostructures with desired shapes and phases on substrates of different orientations that is increasingly required for advanced device applications.…”