Growth by molecular beam epitaxy and properties of inclined GaN nanowires on Si(001) substrate

Abstract

The growth mode and structural and optical properties of novel type of inclined GaN nanowires (NWs) grown by plasma-assisted MBE on Si(001) substrate were investigated. We show that due to a specific nucleation mechanism the NWs grow epitaxially on the Si substrate without any Si(x)N(y) interlayer, first in the form of zinc-blende islands and then as double wurtzite GaN nanorods with Ga-polarity. X-ray measurements show that orientation of these nanowires is epitaxially linked to the symmetry of the substrate so that [0001] axis of w-GaN nanowire is directed along the [111]Si axis. This is different from commonly observed behavior of self-induced GaN NWs that are N-polar and grow perpendicularly to the surface of nitridized silicon substrate independently on its orientation. The inclined NWs exhibit bright luminescence of bulk donor-bound excitons (D(0)X) at 3.472 eV and exciton-related peak at 3.46 eV having a long lifetime (0.7 ns at 4 K) and observable up to 50 K.

Quantified hole concentration in AlGaN nanowires for high-performance ultraviolet emitters

“…3(d), the diffracted X-ray beam intensity distributions are located in the center of the pole figure, which indicates that the c-axis of most of the AlGaN nanowires is perpendicular to the substrate and agrees with the θ-2θ scan result. 64,65 Moreover, a distribution of the tilt angles of the AlGaN nanowires with the [0002] axis is also expected because of the rough substrate surface. Fig.…”

High-resolution X-ray diffraction analysis of strain distribution in GaN nanowires on Si(111) substrate

“…Before the growth started, the substrate was exposed to a nitrogen flux for 30 min at the nitridation temperature of approximately 150°C. The procedure of plasma-assisted MBE growth of GaN NWs on Si(111) is described in [10,11]. The high-resolution X-ray diffraction measurements were performed by using PANalytical X'Pert Pro MRD diffractometer (PANalytical, Almelo, the Netherlands) equipped with a 1.6 kW X-ray tube (vertical line focus) with Cu K α 1 radiation ( λ  = 1.540598 Å), a symmetric 4 × Ge(220) monochromator and a channel-cut Ge(220) analyzer.…”

A Flexible GaN Nanowire Array‐Based Schottky‐Type Visible Light Sensor with Strain‐Enhanced Photoresponsivity

“…[ 26 ] According to the strong PL emission in the visible region of 400 to 750 nm, the CVD-grown GaN nanowires have deep energy levels or bands in the GaN band gap, which shows the effective electron states for electronic transition and visible photoelectric conversion. [17][18][19][20][21][22][23] Recently, the piezophototronic effect was used to improve the performance of photodetectors. To determine the photoresponse performance of the fl exible Flexible optoelectronic devices are of great interests in various applications, including rollable displays, soft touchscreens, fl exible solar cells, and fl exible solid-state lighting, because they can be fabricated with a large area, are low in cost and fi t various surfaces.…”