Growth of GaN micro/nanolaser arrays by chemical vapor deposition

Abstract

Optically pumped ultraviolet lasing at room temperature based on GaN microwire arrays with Fabry-Perot cavities is demonstrated. GaN microwires have been grown perpendicularly on c-GaN/sapphire substrates through simple catalyst-free chemical vapor deposition. The GaN microwires are [0001] oriented single-crystal structures with hexagonal cross sections, each with a diameter of ∼1 μm and a length of ∼15 μm. A possible growth mechanism of the vertical GaN microwire arrays is proposed. Furthermore, we report room-temperature lasing in optically pumped GaN microwire arrays based on the Fabry-Perot cavity. Photoluminescence spectra exhibit lasing typically at 372 nm with an excitation threshold of 410 kW cm(-2). The result indicates that these aligned GaN microwire arrays may offer promising prospects for ultraviolet-emitting micro/nanodevices.

a-Axis GaN/AlN/AlGaN Core–Shell Heterojunction Microwires as Normally Off High Electron Mobility Transistors

“…The inevitable damages of materials and crystal structures as well as surface defects, however, are caused by dry or wet etching during the top-down process, which brings about the degradation of device performance. Therefore, a large body of investigations on III-nitride wires is based on the bottom-up strategy, which provides a better flexibility in controlling the device architectures, and different synthesis techniques, including chemical vapor deposition (CVD), metalorganic chemical vapor deposition (MOCVD), − and molecular beam epitaxy (MBE) , have been developed within this category. However, most of the reported III-nitride wires have a vertically self-assembled growth along [0001] crystallization direction on substrates, which results in the shell epilayers deposited on nonpolar sidewalls when growing core–shell structures or the heterojunctions formed on axial direction. , As for the former, the reduced polarization electric field along nonpolar crystal orientation is advantageous to improve quantum efficiency for light-emitting devices but it imposes restrictions on applications for HEMT devices, where the carrier gas is in close relationship with the polarity.…”

Modulation Effects of Hydrogen on Structure and Photoluminescence of GaN Nanowires Prepared by Plasma-Enhanced Chemical Vapor Deposition

“…However, the effects of hydrogen on modulating the GaN structure are still not clear from these studies. Most III–V NWs grown experimentally exhibit a wurtzite structure with a hexagonal prism morphology, − although a triangular pyramid morphology is occasionally observed . We previously reported a low cost and green method for the large-scale preparation of high quality GaN NWs, by plasma-enhanced chemical vapor deposition (PECVD) without using ammonia. , However, it is also difficult to regulate the size and morphology of the GaN NWs using only these simple process parameters.…”

GaN Ultraviolet Laser based on Bound States in the Continuum (BIC)

“…GaN with a wide direct bandgap of 3.41 eV at room temperature is the technological material employed for UV laser diodes. With the advanced of growth techniques such as metal-organic chemical vapor deposition (MOCVD) and vapor phase epitaxy growth method, [25,26] high-quality GaN can be readily deposited so that GaN-based UV lasers have been realized using singlecrystal GaN film, [27,28] Fabry-Perot nanowire cavities, [29][30][31][32][33] whispering-gallery-mode cavities, [34][35][36][37][38] and vertical cavity surface emitting lasers (VCSEL). [39,40] For random scattering lasers, Fabry-Perot lasers, and whispering-gallery-mode lasers, out-ofplane directional emission lasing remains difficult to achieve.…”