Nanomanipulating and Tuning Ultraviolet ZnO-Nanowire-Induced Photonic Crystal Nanocavities

Abstract

We report on the fabrication, nanomanipulation, and optical properties of ZnO-nanowire-induced nanocavities in grooved SiN photonic crystals. We show that subwavelength ZnO nanowires supporting intrinsically no Fabry−Peŕot mode in the violet and near-ultraviolet range can induce optical confinement when introduced in a grooved twodimensional photonic crystal waveguide. Despite fabrication challenges arising at such short wavelengths, this hybrid approach leads to fundamental nanocavity modes with resolution-limited quality factors larger than Q exp = 2.1 × 10 3 at λ = 403 nm for a mode volume V m = 5.9(λ/n r NW ) 3 = 3.4(λ/n r SiN ) 3 , as deduced from three-dimensional finite-difference timedomain calculations. The investigation of optical losses in our system shows that at wavelengths shorter than λ = 390 nm Q exp is limited by self-absorption, indicating a good nanowire to cavity coupling. These results validate our hybrid approach as an efficient way to circumvent the processing issues that were so far preventing the insertion of ZnO emitters in photonic crystal nanocavities. Furthermore, we demonstrate that the degree of freedom along the groove can be used to move nanowire-induced nanocavities in space, position them deterministically, and tune their optical properties in the near-ultraviolet range. This striking feature opens the path toward the realization of versatile nanophotonic devices including movable and tunable all-dielectric NW nanolasers operating at high temperature.

Hybrid Nanowire Photodetector Integrated in a Silicon Photonic Crystal

“…With only a couple percent of the electric field in this particular waveguide mode confined within the nanowire, it is a prominent problem with the device. However, the nanowires fabricated by subliming substrates or other growth conditions allow for rectangle cross sections that fit better into the trench, thereby minimizing the air gap and increasing field confinement up to dozens of percent . In addition, if the PhC’s optimal wavelength was tuned for material gain, the light absorption can also be improved 5–10× more than the current condition.…”

Localized Energy Band Bending in ZnO Nanorods Decorated with Au Nanoparticles

“…Zinc oxide (ZnO) is an n -type semiconductor (band gap of 3.2–3.4 eV, large excitonic-binding energy of 60 meV) attracting great attention due to its physical and chemical properties [ 1 , 2 ]. In particular, ZnO nanorods (NRs) have proven to be promising nanostructures for a wide range of applications, especially for photonics and optoelectronics in the UV or blue spectral range [ 3 , 4 , 5 , 6 , 7 , 8 , 9 ]. A controlled improvement of performance needs a microscopic understanding of ZnO surface states and deep levels, especially in low-dimensional nanostructures where the significant surface-to-bulk ratio significantly impacts electronic energy band bending.…”

Effects of N implantation on defect formation in ZnO nanowires

“…One-dimensional ZnO nanowire (NW) structures have recently attracted a substantial scientific and technological interest as building blocks for a wide range of optoelectronic and photonic applications, such as ultraviolet light emitting diodes, solar cells, photo detectors, as well as gas sensors and photocatalysts [1][2][3][4][5][6][7][8]. These structures have the advantage of combining the material properties of ZnO, namely its wide and direct band gap (~3.3 eV at room temperature) and a large exciton binding energy (60 meV at room temperature), with those of nanoscale objects including a high surface-to-volume ratio, the freedom to design axial and lateral heterostructures, light trapping and reduced material consumption.…”