Single-crystalline aluminum film for ultraviolet plasmonic nanolasers

Abstract

Significant advances have been made in the development of plasmonic devices in the past decade. Plasmonic nanolasers, which display interesting properties, have come to play an important role in biomedicine, chemical sensors, information technology, and optical integrated circuits. However, nanoscale plasmonic devices, particularly those operating in the ultraviolet regime, are extremely sensitive to the metal and interface quality. Thus, these factors have a significant bearing on the development of ultraviolet plasmonic devices. Here, by addressing these material-related issues, we demonstrate a low-threshold, high-characteristic-temperature metal-oxide-semiconductor ZnO nanolaser that operates at room temperature. The template for the ZnO nanowires consists of a flat single-crystalline Al film grown by molecular beam epitaxy and an ultrasmooth Al2O3 spacer layer synthesized by atomic layer deposition. By effectively reducing the surface plasmon scattering and metal intrinsic absorption losses, the high-quality metal film and the sharp interfaces formed between the layers boost the device performance. This work should pave the way for the use of ultraviolet plasmonic nanolasers and related devices in a wider range of applications.

Surface roughness effects on aluminium-based ultraviolet plasmonic nanolasers

“…In our previous study13, we extracted the permittivity of Al films by fitting the measured reflectivity spectra with the Drude-Lorentz model. However, a discrepancy exists between the model fitting results and measured reflectivity spectra for UV wavelengths.…”

“…For example, intrinsic ohmic damping and extrinsic scattering loss can crucially compromise the propagation length of surface plasmon waves with wavelengths in the ultraviolet (UV) regime. Consequently, the surface roughness and crystalline quality of the metallic layer is the essential factor in determining the performance of plasmonic nanolasers or cavities13. Some plasmonic nanocavities and nanolasers on high quality metallic films have been realised and have shown superior lasing characteristics68.…”

“…The sample fabricated by molecular beam epitaxy system is single-crystalline (sample A) and the sample fabricated by electron-gun evaporator is polycrystalline (sample B). In the proposed structures, the hybrid plasmonic gap modes, concentrated inside the dielectric gaps between the gain material nanowires and metallic interfaces, are the most promising modes for lasing67891013. Since the guided plasmonic mode profiles strongly overlap with the thin gaps, the increase in intrinsic modal loss caused by surface scattering and ohmic damping from SPPs on the rough metallic surface can be significant.…”

Topological Transition in a 3 nm Thick Al Film Grown by Molecular Beam Epitaxy

“…Aluminum (Al) is the most abundant metal on the Earth's crust, and it has already found wide applications in interconnects, coating on graphene, plasmonic devices, and so on [12][13][14]. Recent advances in sample preparation have made it possible to prepare large-area, high-quality Al films [14,15].…”

Single Plasmon Generation in an InAs/GaAs Quantum Dot in a Transfer-Printed Plasmonic Microring Resonator

“…Another important issue is to employ high quality plasmonic structures in order to maximize the SPG performances including single plasmon generation efficiency. It should be avoided to use rough metal surfaces for supporting SPP modes, since they scatter photons out of the SPP modes and can be a source of unwanted loss in SPGs [19][20][21] .…”