Molecular beam epitaxial growth and characterization of non-tapered InN nanowires on Si(111)

Abstract

We have performed a detailed investigation of the molecular beam epitaxial growth and characterization of InN nanowires spontaneously formed on Si(111) substrates under nitrogen rich conditions. By employing an in situ deposited thin (approximately 0.5 nm) In seeding layer prior to growth initiation, we have achieved, for the first time, non-tapered epitaxial InN nanowires, which exhibit record narrow spectral linewidths of 14 and 40 meV at 5 K and 300 K, respectively. Detailed studies confirm that the wires are nearly free of dislocations and stacking faults. The achievement of non-tapered, nearly homogeneous InN nanowires also enables, for the first time, the derivation of the band gap of InN directly from PL spectroscopy in the temperature range of 5-300 K.

Understanding the role of Si doping on surface charge and optical properties: Photoluminescence study of intrinsic and Si-doped InN nanowires

“…Detailed transmission electron microscopy (TEM) studies further confirm that such undoped InN nanowires are nearly free of defects and dislocations. 12 It should be noted that this non-tapered hexagonal structure can be achieved in InN:Si nanowires as well (HRSEM images not shown here). In this study, experiments (unless otherwise states) were performed on InN nanowires with lengths of ∼ 0.7 − 0.8 µm.…”

“…The detailed growth procedures were described elsewhere. 12,46 High-resolution scanning electron microscopy (HR-SEM) image of undoped InN nanowires is shown in Fig. 1, which exhibits near-perfect hexagonal structure.…”

“…InN, after being discovered of a narrow bandgap (E g ∼ 0.65 − 1 eV) [1][2][3][4][5][6][7][8][9][10][11][12][13][14] and predicted to possess the largest electron mobility among group-III nitrides (∼ 4400 cm 2 ·V −1 ·s −1 at 300 K), 15 has emerged as a highly promising material for infrared photodetectors and lasers, solar cells, ultrahigh-speed transistors, and sensors. [16][17][18] To date, however, the practical device applications of InN-based materials have been severely limited by the presence of extremely large residual electron density and the uncontrolled surface charge properties, as well as the difficulty in achieving p-type conductivity.…”

“…12,13,46 With such low residual electron density, studying the fundamental carrier dynamics, as well as the correlated electrical and optical properties of InN nanowires with controlled charge carrier concentration becomes possible.…”

Recent Advances on p-Type III-Nitride Nanowires by Molecular Beam Epitaxy

“…In fact, a number of recent studies indicate that the MBE-grown III-nitride nanowires could be substrate independent [95][96][97][98][99], i.e., the MBE-grown III-nitride nanowires can be essentially formed on any substrate. For example, GaN, InGaN/GaN dot-in-a-wire, and InN nanowire structures have been demonstrated on silicon oxide [95,[99][100][101].…”