Richarda Niemann
Vanderbilt University, Nashville, Tennessee, USA _______________________________________
As the application spaces enabled by hBN due to its exemplary material properties, research towards new growth methods is also continuing to expand. By now, a variety of techniques exist to grow bulk hBN crystals, as well as thin multi- and monolayer films [1]. In the case of the former, these crystals can be used to exfoliate thin flakes, but wafer-scale layers are not possible. In the latter, the layers can be wafer-scale but getting thicknesses on the order of 100’s of nm or thicker has not been demonstrated. Recently, a new approach for hBN growth based on a modified flux method was developed, providing large and uniform hBN films of various thicknesses in this intermediate regime.
Here, we investigate the applicability of these films in two main hBN research areas: (1) as a naturally hyperbolic material capable of hosting propagating phonon polaritons [2] and (2) as a medium for generating single photons at room temperature over a broad spectral emission range [3].
For characterizing the propagation characteristics of hBN phonon polaritons, we deposit Au launchers onto the film and performed scattering-type scanning near-field optical microscopy (s-SNOM) experiments. Samples with different film thicknesses will provide a more complete picture of the influence on the hyperbolic and polaritonic behavior of the material. We furthermore test the natural capability of hBN to emit single photons by µ-PL mapping and subsequent Hanbury Brown-Twiss interferometry. Our experiments will provide insight into the broad applicability of these wafer-scale intermediate thickness (50-500 nm) hBN films grown with the modified flux method for current hBN research questions.
References:
[1] Naclerio et al., Adv. Mater. 2023, 35, 2207374
[2] Caldwell et al., Nature Communications 5, 5221 (2014)
[3] Tran et al., Nat. Nano-technol. 2016, 11, 37 of Nanoporous Hexagonal Boron Nitride (h-BN) for Large-Area Atomically Thin Ceramic Membranes. NanoLetters. 2025, Accepted.
Email: richarda.niemann@vanderbilt.edu