Light Output Improvement of GaN-Based Light-Emitting Diodes Using Hydrothermally Grown ZnO Nanotapers

Abstract

A new two-step hydrothermal growth (HTG) process with a shorter processing time and better growth control is proposed for the synthesis of ZnO nanotapers (NTs). The application of HTG ZnO NTs as surface roughening nanostructures to improve the light output power (L op) of GaN-based LEDs is demonstrated. Compared with that of ZnO nanowires, the use of ZnO NTs leads to an improvement in L op by 24.5% at 350 mA, which could be attributed to the fact that tapered ends of ZnO NTs offer more constructive photon scattering to maximize light extraction.

Influence of surface nitridation and an AlN buffer layer on the growth of GaN nanostructures on a flexible Ti metal foil using laser molecular beam epitaxy

“…The stress (σ) present in GaN nanostructures can be estimated from the following equation: 34,35) s w w = -( ) 4. 3 1…”

“…GaN nanostructures are attractive for various energy applications such as light-emitting diodes (LEDs), laser diodes, solar cells and photocatalysts in chemical hydrogen production due to their excellent optoelectronic properties and stability in harsh environments. [1][2][3][4][5][6][7] Recently, the growth of one-dimensional (1D) GaN nanostructures on metal substrates has attracted special attention due to their direct back contact, high optical reflectivity and good thermal and electrical conductivities, which are limited with conventional substrates such as sapphire and silicon. [8][9][10] Few reports in the literature have presented the growth of 1D GaN nanostructures on various metal substrates.…”

Hydrothermal Growth of Quasi-Monocrystal ZnO Thin Films and Their Application in Ultraviolet Photodetectors

“…The material properties of the prepared ZnO film were analyzed by XRD and PL, with the results shown in Figure 2. On the basis of the diffraction peak that corresponded to the (002) plane shown in Figure 2(a), the ZnO film fabricated via HTG was indexed to have a hexagonal wurtzite signal according to the standard JCPDS card [25]. This indicates that ZnO films fabricated via HTG are mainly formed via self-organized growth interconnections of closely packed crystalline columnar ZnO with the -axis vertical to the substrate surface.…”

Improving Crystalline Silicon Solar Cell Efficiency Using Graded-Refractive-Index SiON/ZnO Nanostructures

“…Zinc oxide (ZnO) is a promising material for surface roughening. It has a wide direct band gap (3.37 eV at room temperature), large exciton binding energy (about 60 meV) [10,11], and transmittance of about 85% in the visible region [12,13]. One-dimensional ZnO nanowire (NW) arrays have received great attention due to their ease of fabrication, low-temperature processing, and unique properties, such as large length-to-diameter ratio, high surface-to-volume ratio, and carrier confinement, which could improve device performance [6,[14][15][16].…”