Annular-Shaped Emission from Gallium Nitride Nanotube Lasers

Abstract

Annular-shaped lasing emission is demonstrated from gallium nitride nanotubes fabricated using a two-step top-down technique. By optically pumping, we observe a clear threshold of 1055 kW/cm 2 , a narrow spectral linewidth of 0.19 nm, and guided emission from the

Nonpolar InGaN/GaN Core–Shell Single Nanowire Lasers

“…The optical setup has been described in detail previously. 10,17 A pulsed, 266 nm frequency-quadrupled Nd:YAG laser was utilized to optically pump the core−shell nanowires. The short pulse width (400 ps pulse width, 10 kHz repetition rate) of the pump laser minimizes heating effects during optical pumping.…”

“…Semiconductor single nanowire lasers have garnered heavy interest as potential low threshold, low power requirement, compact and integrable coherent light sources for wide-ranging applications, such as very large scale photonic integrated circuits, high-speed communications, optical probes, and sensing . Because of the advantages of the III-nitride (AlGaInN) semiconductor materials system, including their direct bandgaps, broad spectral range from the UV to near-infrared, low surface state density, and large exciton binding energies, GaN-based single-nanowire lasers have been among the most heavily studied. − ,− …”

“…However, most single nanowire lasers demonstrated thus far consist of homogeneous, single composition materials (e.g., GaN, GaAs, or ZnO). − ,− Thus, the lasing emission is limited to specific wavelengths corresponding to the fundamental bandgap. More importantly, for achieving monolithic, integrable electrically injected single nanowire light-emitting didoes (LEDs) and lasers, a p-i-n diode heterostructure architecture is likely necessary.…”

“…The core–shell nanowires were dry transferred onto a Si 3 N 4 /Si substrate using a cotton swab for μ-PL characterization at room temperature. The optical setup has been described in detail previously. , A pulsed, 266 nm frequency-quadrupled Nd:YAG laser was utilized to optically pump the core–shell nanowires. The short pulse width (400 ps pulse width, 10 kHz repetition rate) of the pump laser minimizes heating effects during optical pumping.…”

Thin-Wall GaN/InAlN Multiple Quantum Well Tubes

“…The optical properties of all these thin-wall tubes are usually not reported or are altered due to the presence of surface states . Only tubes with thick enough walls (typically >100 nm) exhibit significant optical properties, as reported by Li et al with lasing emission based on thick-wall GaN tubes fabricated using a top-down GaN etching process using ordered ringlike patterns . Therefore, the issues related to the low optical quality of thin-wall tubes and their difficulties of fabrication strongly limit the development of such III-N tube-like nanostructures and require to be further addressed.…”