Synthesis, microstructure, growth mechanism and photoluminescence of high quality [0001]-oriented InN nanowires and nanonecklaces

Abstract

Novel indium nitride (InN) based nanomaterial is important for high speed electronics and infrared optoelectronics. In this paper, high quality Indium nitride (InN) nanostructures including nanowires and nanonecklaces, have been grown on one substrate by chemical vapor deposition. The morphologies and microstructures of InN nanowires and nanonecklaces were characterized, which confirmed their chemical composition as well as single crystallinity. The InN nanonecklaces consist of multiple beads composed of two equilateral truncated hexagonal cones faceted with { } 1 1 10 and { } 1 1 10 planes. The growth mechanism of the InN nanonecklace was studied and a three-step process was suggested for the growth. Finally, room temperature photoluminescence spectra of the two nanostructures showed the near band edge emissions of around 0.73 eV, where the emission from nanonecklace was found to be stronger, indicating the promise for near-infrared optoelectronics applications.Group III nitride semiconductors are extensively studied materials in the last two decades for broad technologies ranging from light emitters to fast electronics. Among them, much effort was dedicated to the study of InN for its distinguished physical and chemical properties [1][2][3][4][5] , especially the high electrical conductivity and electron mobility. These merits may lead to potential applications in high speed electronic devices, terahertz spectroscopy [6] , biosensors [7] , solar cells [8] , Fig. 5 TEM and HRTEM images of the InN nanowire and InN nanonecklace. (a) TEM image of an individual nanowire, (b) The corresponding HRTEM image and SAED pattern of the nanowire. (c) TEM image of an individual nanonecklace, (d) The corresponding HRTEM image and FFT pattern of the nanonecklace. (e) Space-filling model of ideal [0001] nanonecklace and schematic representation of Miller indexing of the various faces of crystal (left) and the corresponding crystal unit of the InN nanonecklace (right).Moreover, it should be noted that the above theoretical analysis is based on stoichiometric and ideal slow growth condition. In reality, the growth is also subject to other factors. In the case here, the In/N source ratio would render drastically different growth patterns like nanowires/nanonecklace. This phenomenon is commonly occurred in nanomaterial growth. For example, one CVD growth can yield six different morphologies in Gallium Sulfide structures [41] .Here the detailed theoretical analysis beyond BFDH method is not conducted, since this report is mainly focused on the experiment growth demonstration of peculiar InN nanostructures. 1 1 10 planes possess finite charges and dipole moments, they will give a rise to inversely positive and negative electrostatic surface energy. To keep the overall structure stable, the total surface free energy including the electrostatic surface energy and the surface

Controllable Synthesis of [11−2−2] Faceted InN Nanopyramids on ZnO for Photoelectrochemical Water Splitting

“…), efficient charge separation and migration, and band gap tuning for matching the potentials of water reduction and oxidation. Among them, InN, as a representative group III–V nitride semiconductor, has also been identified as one of the most promising photoelectric materials for its narrow band gap of ≈0.7 eV at 300 K, high electron saturation velocity (1.5 × 10 7 cm s −1 ) and electron mobility of 14 000 cm 2 (Vs) −1 , large intervalley spacing (2.7 eV) to confine carriers, which with these merits may lead to its potential applications in PEC water splitting . However, widespread use of InN in PEC water splitting is still hindered by the difficulties in growing high quality InN samples.…”

Morphology and composition evolution of one-dimensional InxAl1−xN nanostructures induced by the vapour pressure ratio

“…For group III nitrides, the direct bandgap can be adjusted from 6.2 eV for AlN, through 3.4 eV for GaN, to 0.7 eV for InN, 11 which makes the 1D nanostructures of group III nitrides have great potential in advanced nano-and optoelectronic devices. [12][13][14][15][16][17][18][19][20] Various morphologies of binary nitrides (AlN, GaN, InN) have been fabricated by numerous methods; however, the synthesis of alloyed nitrides with 1D geometries is highly challenging because phase separation usually happens due to the large lattice mismatch between the two corresponding binary nitrides. Very recently, 1D nanostructures of ternary InGaN and AlGaN have been synthesized with continuously regulated compositions in the entire range, which exhibit tunable optical and electronic properties accordingly.…”