Résumé
MBE Growth of Mid-Infrared Lasers on Silicon Eric Tournié, M. Rio Calvo, L. Monge-Bartolome, A. Gilbert, A. Remis, M. Paparella, D. Andres Thomas, Z. Loghmari, R. Teissier, A. N. Baranov, L. Cerutti, and J.-B. RodriguezIES, University of Montpellier, CNRS, Montpellier, FranceAmong “More-than-Moore” strategies, the integration of optical devices with Silicon has attracted much attention. Indeed, mastering efficient light-emitting, energy harvesting, or light-engineering systems on silicon not only holds several advantages for present technologies (e.g., silicon photonics, photovoltaics, or sensors), but it could open novel paradigms in photonics, computing or energy harvesting and storage applications (e.g., integrated quantum photonics, all-optical neuromorphic computing, or solar water splitting). The epitaxial hybridization of III-V devices on Si however has long been hampered by the high defect density generated during the growth. One of the issues arises from the non-polar diamond crystal structure of Si, whereas III-V materials (but III-N compounds) have a polar zinc-blende crystal structure. This generally results in the nucleation of III-V anti-phase domains (APDs), and generates anti-phase boundaries (APBs) where main and anti-phase domains intersect. APBs create shorts and are device killers in most devices. After reviewing these issues and the current understanding , I will present strategies to eliminate APBs with a focus on the GaSb-on-Si case system. I will show how specific Si substrate preparation and III V-on-Si nucleation allow achieving APB-free GaSb-based layers and heterostructures on on-axis (001)Si substrates. More precisely, on a properly prepared Si surface, the different growth rates of the main and anti-phase domains results in the main domain overgrowing the APDs. Consequently, APBs are buried within the buffer layer after a thickness that depends on the residual Si miscut angle. Such “emerging-APB-free” GaSb-on-Si layers have been used as templates for the subsequent growth of a variety of mid-infrared lasers. The I – V characteristics of GaSb diode lasers emitting near 2.3 µm confirmed that APBs are no more an issue in these structures. Low threshold current-densities and high T0 characteristic of the devices have been obtained. Their threshold current density was however sensitive to the threading-dislocation density. In contrast, InAs/AlSb quantum cascade lasers emitting near 8 µm demonstrated performances similar to those on native InAs substrates, thanks the unipolar nature of the radiative process. Finally, at intermediate wavelength (3.5 µm), InAs/GaInSb type-II interband cascade lasers also proved to be relatively insensitive to dislocations, which is ascribed to their particular band structure. These results open the route to active photonic integrated circuits operating in the mid-infrared for sensing applications. Part of this work was sponsored by the French program on “Investments for the Future” (EquipEx EXTRA, ANR-11-EQPX-0016), the French ANR (ANR14-CE26-0014, ANR-16-CE24-0011) and the H2020 program of the European Union (project REDFINCH, GA 780240 ; OPTAPHI, GA 860808).References: I. Lucci et al., Phys. Rev. Mat. 2, 060401(R) (2018). https://doi.org/10.1103/PhysRevMaterials.2.060401 C. Cornet et al., Phys. Rev. Mat. 4, 053401 (2020). https://doi.org/10.1103/PhysRevMaterials.4.053401. M. Rio Calvo et al., Adv. Electron. Mat. 8(1), 202100777 (2022). https://doi.org/10.1002/aelm.202100777 M. Rio Calvo, L. Monge Bartolomé, et al., Optica, 7(4), 263 (2020). https://doi.org/10.1364/OPTICA.388383 Z. Loghmari et al., APL Phot. 5, 041302 (2020). https://doi.org/10.1063/5.0002376. L. Cerutti et al., Optica, 8(11), 1397 (2021). https://doi.org/10.1364/OPTICA.438272 E. Tournié et al., Light: Science & Applications. https://doi.org/10.1038/s41377-022-00850-4