Catalyst-free growth of InAs/InxGa1−xAs coaxial nanorod heterostructures on graphene layers using molecular beam epitaxy

Abstract

We report the catalyst-free growth of InAs/In x Ga 1 − x As coaxial nanorod heterostructures on large-area graphene layers using molecular beam epitaxy and our investigation of the chemical composition and crystal structure of these heterostructures using electron microscopy. The graphene layers used as the substrate were prepared by chemical vapor deposition and transferred onto SiO 2 /Si substrates. InAs nanorods and their heterostructures were grown vertically on the graphene layers; electron microscopy images revealed uniform distributions for their diameter, length and density. Cross-sectional electron microscopy images showed that In x Ga 1 − x As layers, having uniform composition, coated heteroepitaxially the entire surface of the InAs nanorods, without interfacial layers or structural defects. The catalyst-free growth mechanism of InAs nanorods on graphene was investigated using in situ reflection high-energy electron diffraction.

GaN/AlGaN Nanocolumn Ultraviolet Light-Emitting Diode Using Double-Layer Graphene as Substrate and Transparent Electrode

“…An intriguing potential substrate for epitaxial growth of semiconductors is graphene, the single-layer form of carbon, as it can not only act as an atomically thin crystalline growth template but also has outstanding functional properties when it comes to strength, flexibility, and electron and thermal conductivity. , Hybrid systems based on the growth of semiconductor nanocolumns on different graphitic substrates have been intensively studied in the past decade with the aim of developing new functionalities and higher efficiency optoelectronic devices as, for example, solar cells, photodetectors, light-emitting diodes (LEDs) and lasers. Such hybrid systems have been demonstrated for GaAs, InAs, − InAsSb, In­(Ga)­As, , ZnO, , and GaN. With regards to the growth of GaN nanocolumns, different graphitic forms have been used as growth substrate, for instance, graphite, transferred chemical vapor deposition (CVD) graphene (single- and multilayer), − and epitaxial graphene .…”

“…4,5 Hybrid systems based on the growth of semiconductor nanocolumns on different graphitic substrates have been intensively studied in the past decade with the aim of developing new functionalities and higher efficiency optoelectronic devices as, for example, solar cells, photodetectors, light-emitting diodes (LEDs) and lasers. Such hybrid systems have been demonstrated for GaAs, 6 InAs, 7−9 InAsSb, 10 In(Ga)As, 11,12 ZnO, 13,14 and GaN. With regards to the growth of GaN nanocolumns, different graphitic forms have been used as growth substrate, for instance, graphite, 15 transferred chemical vapor deposition (CVD) graphene (single-and multilayer), 16−25 and epitaxial graphene.…”

MBE growth of self-assisted InAs nanowires on graphene

“…Moreover, graphene is a low cost substrate that has high mechanical strength and flexibility, excellent electrical properties and optical transparency. The direct growth of semiconductor NWs on graphene has already been demonstrated, mainly using metal-organic chemical vapor deposition [23][24][25][26][27][28][29][30][31][32]. In particular, self-assisted van der Waals growth of InAs NWs on graphene was shown to be an alternative to that on Si/SiO 2 [29][30][31][32].…”

“…In the last few years Munshi et al showed that MBE can be used to obtain GaAs NWs on graphene [25,28]. Zhuang et al demonstrated In droplet-assisted MBE growth of InAs nanorods on mechanically exfoliated graphite flakes [31], and quite recently Tchoe et al obtained core/shell InAs/InGaAs coaxial nanorod heterostructures on graphene layers using MBE [32]. The development of a catalyst-free MBE growth method to produce ultrapure InAs NWs with controllable morphological and structural properties is of great importance.…”

“…The direct growth of semiconductor NWs on graphene has already been demonstrated, mainly using metal-organic chemical vapor deposition [23][24][25][26][27][28][29][30][31][32]. In particular, self-assisted van der Waals growth of InAs NWs on graphene was shown to be an alternative to that on Si/SiO 2 [29][30][31][32]. A VLS/VS growth mechanism guided by a small persistent indium droplet, at least during the initial stage of the growth, assures the vertical growth, yet often having highly disordered crystal structure and significant side growth [28,30].…”