This work investigates hexagonal Boron Nitride (hBN), being a promising source of single photons, with a home-built confocal microscope. Using colloidal quantum dots as a reference, the setup was...Show moreThis work investigates hexagonal Boron Nitride (hBN), being a promising source of single photons, with a home-built confocal microscope. Using colloidal quantum dots as a reference, the setup was optimized and characterized. All in all it showed decent efficiency and resolution, close to the limit of the current objective. The hBN sample, provided by a scientific group in Denmark, was investigated in two stages. First, primary investigation revealed that there are two types of flakes present on the sample; we call them flat and fluffy flakes. They were observed using pump reflection, fluorescence and darkfield imaging. All measurements present clear distinction between the flakes including difference in form, structure, fluorescent and reflective properties. Fluffy flakes show larger absolute strength of fluorescence signal and pump reflection. Bleaching measurements indicate greater stability of flat flakes compared to fluffy flakes. In the second stage, special defects on the flat flakes were studied by means of spectral and lifetime measurements. These defects were found using position-resolved spectral scans. Some of the defects show spectra with two-peak structure and prominent spectral lines, resembling those reported in literature. Spectra of fluffy flakes present uniform distribution of bulk fluorescence. This research is a stepping stone to a better understanding of single-photon fluorescent defects in 2D materials.Show less
To better understand the LEEM spectra of 2D materials we explored usingtransfer matrices to model them. We applied transfer matrices to find ananalytical expression for the LEEM spectra of graphite...Show moreTo better understand the LEEM spectra of 2D materials we explored usingtransfer matrices to model them. We applied transfer matrices to find ananalytical expression for the LEEM spectra of graphite. We found that itresults in an approximate solution that correctly predicts the position ofthe minima and general shape of the curve in the 0-25 eV range. We alsoapplied transfer matrices to model the spectrum of few-layer grapheneon bulk hexagonal boron nitride. The modeling of graphene on hBN wasdone in a coherent, incoherent and a modified coherent case. We foundthat the model manages to show the 8 eV minima in the coherent case.But the general shape we found is less accurate than for graphite. Theother cases did not model the 8 eV dip of the spectra.Show less
