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ALT'23 The 30th International Conference on Advanced Laser Technologies
LD-O-4
Features of the band structure in the luminescence response of 2D photonic crystals with Ge(Si) nanoislands
A. Peretokin1,2, M. Stepikhova1, S. Dyakov3, D. Yurasov1, M. Shaleev1, D. Shengurov1, E. Rodyakina4, Sh. Smagina4, A. Novikov12
1-Institute of Physics of Microstructures RAS, st. Akademicheskaya, 7, 1 Afonino, Kstovsky district, Nizhny Novgorod
region, Russia
2- UNN them N.I. Lobachevsky, Gagarin Ave., 27, Nizhny Novgorod, Russia 3- Institute of Semiconductor Physics A.V. Rzhanov SB RAS, 13 Lavrentiev Ave.,
Novosibirsk, Russia
4 - Skolkovo Institute of Science and Technology, st. Nobelya, 3, Moscow, Russia
aperetokin@ipmras. ru
To date, the problem associated with creation of effective silicon-based sources for the near-infrared range remains unresolved. One of the possible solutions to this problem are photonic crystals (PhC) with Ge(Si) nanoislands. In these structures, luminescence is observed in the wavelength range of 1.2-1.6 ^m at room temperature [1]. The introduction of Ge(Si) nanoislands into PCs makes it possible to enhance their luminescent response by more than two orders of magnitude due to the interaction with distinct photonic modes [2]. A strong enhancement of the luminescence response is observed when the spectral position of PhC modes coincides with the maximum of nanoislands luminescence spectrum. In this work, we will show the possibilities to manage PhCs band structure depending on their parameters.
The luminescence response of PhCs that were fabricated on Si structures with self-assembled Ge(Si) nanoislands was analyzed depending on lattice period (a), r/a ratio, where r - is the hole radius, and hole depth (h) of PhCs. To analyze PhCs band structure, an original method for measuring the luminescence signal with angular resolution was used [3]. Measurements carried out with this technique allow us to restore the band structure of PhCs with good accuracy.
We will show the presence in luminescent response of PhCs of bound states in the continuum (BIC). The symmetry-protected BICs appear at the r point of Brillouin zone for both singlet and doublet photonic modes, and are manifested by thin lines in the luminescence spectra [2,4]. The quality factor of these lines (Q) can reach 2600. At certain parameters of PhCs, a flat zone with the symmetry-protected BIC can be formed. The latter is characterized by a near to zero group velocity [5]. Moreover, accidental BICs, modes anticrossing and so-called "hot-spots", which are related with the interaction of photonic modes in PhCs were also observed. Appearance of these phenomena in luminescence response of PhCs and their correlation with PhCs parameters will be discussed.
The features of the band structure of a PhC described above are of interest from both fundamental and applied points of view. For example, by selecting the parameters of the PhC, it is possible to achieve the combination of SP-BIC and parametric BIC. In this way, the "Super-BIC" state can be achieved, which makes it possible to obtain an extremely narrow lines in the PhC luminescence spectrum [6].
The work was funded by the Russian Science Foundation (grant #19-72-10011).
[1] V.Ya. Aleshkin, N.A. Bekin et al. Self-organization of germanium nanoislands obtained in silicon by molecular-beam epitaxy, JETP Letters,67, p.48 (1998).
[2] S. Dyakov, M. Stepikhova et. al., Photonic bound states in the continuum in Si structures with the self-assembled Ge nanoislands, Laser & Photonics Reviews, 15, p. 2000242, (2021);
[3] A.V. Peretokin, M.V. Stepikhova et al. Photonic crystal band structure in luminescence response of samples with Ge/Si quantum dots grown on pit-patterned SOI substrates, Photonics Nanostructures: Fundam. Appl. 53, p. 101093 (2023).
[4] M. Stepikhova, S. Dyakov et. al., Interaction of Ge(Si) Self-Assembled Nanoislands with Different Modes of Two-Dimensional Photonic Crystal, Nanomaterials, 12, p. 2687, (2022);
[5] A. Peretokin, D. Yurasov et. al., Tuning the Luminescence Response of an Air-Hole Photonic Crystal Slab Using Etching Depth Variation, Nanomaterials, 13, p. 1678, (2023);
[6] M.-S. Hwang, H.-C. Lee et al., Ultralow-threshold laser using super-bound states in the continuum, Nat Commun. 12, p. 4135, (2021).
