III–V ternary nanowires on Si substrates: growth, characterization and device applications

Abstract

Over the past decades, the progress in the growth of materials which can be applied to cutting-edge technologies in the field of electronics, optoelectronics and energy harvesting has been remarkable. Among the various materials, group III-V semiconductors are of particular interest and have been widely investigated due to their excellent optical properties and high carrier mobility. However, the integration of III-V structures as light sources and numerous other optical components on Si, which is the foundation for most optoelectronic and electronic integrated circuits, has been hindered by the large lattice mismatch between these compounds. This mismatch results in substantial amounts of strain and degradation of the performance of the devices. Nanowires (NWs) are unique nanostructures that induce elastic strain relaxation, allowing for the monolithic integration of III-V semiconductors on the cheap and mature Si platform. A technique that ensures flexibility and freedom in the design of NW structures is the growth of ternary III-V NWs, which offer a tuneable frame of optical characteristics, merely by adjusting their nominal composition. In this review, we will focus on the recent progress in the growth of ternary III-V NWs on Si substrates. After analysing the growth mechanisms that are being employed and describing the effect of strain in the NW growth, we will thoroughly inspect the available literature and present the growth methods, characterization and optical measurements of each of the III-V ternary alloys that have been demonstrated. The different properties and special treatments required for each of these material platforms are also discussed. Moreover, we will present the results from the works on device fabrication, including lasers, solar cells, water splitting devices, photodetectors and FETs, where ternary III-V NWs were used as building blocks. Through the current paper, we exhibit the up-to-date state in this field of research and summarize the important accomplishments of the past few years.

Checked patterned elemental distribution in AlGaAs nanowire branches via vapor–liquid–solid growth

“…III-V ternary nanowires (NWs) are particularly advantageous for the realization of optoelectronic devices, due to their direct band gap tunability. 1 This is widely achieved via controlling the distribution and composition of different elements, leading to controllable and tuneable emission in light-emitting applications. [2][3][4] An important phenomenon that is observed often in ternary NWs is the non-uniform compositional distribution, which is sensitive to various NW structural features.…”

Moiré Fringe Method via Scanning Transmission Electron Microscopy

“…GPA is a widely used method to map the strain field from high resolution TEM images based on Fourier‐space‐based data processing, [ 25–31 ] and has been applied for various materials. [ 32–42 ] However, GPA method can be difficult to be directly applied to STEM images, as low‐sampled STEM images often lose detailed information at atomic scale, in addition to other artifacts such as scanning noise and scanning distortions etc. Alternatively, STEM‐MF offers a possibility of strain measurement from STEM images.…”

Preferred growth direction of III–V nanowires on differently oriented Si substrates

“…It is noted that a most intriguing phenomenon regarding epitaxial semiconductor NWs, which is encountered most frequently and reported very often, is that zinc-blende epitaxial NWs prefer to grow along <111> directions, [55,56] Conventionally, people assume that this phenomenon is attributed to the low surface energy of (111) surface. However, through a careful inspection of the literature, it is found that the current understandings on the surface energy could not lead us to the conclusive elucidation of this phenomenon as the surface energy measurements and calculations are based on merely a limited number of specific facets and directions.…”