High-quality CMOS compatible n-type SiGe parabolic quantum wells for intersubband photonics at 2.5–5 THz

Autor: Campagna Elena, Talamas Simola Enrico, Venanzi Tommaso, Berkmann Fritz, Corley-Wiciak Cedric, Nicotra Giuseppe, Baldassarre Leonetta, Capellini Giovanni, Di Gaspare Luciana, Virgilio Michele, Ortolani Michele, De Seta Monica
Jazyk: angličtina
Rok vydání: 2024
Předmět:
Zdroj: Nanophotonics, Vol 13, Iss 10, Pp 1793-1802 (2024)
Druh dokumentu: article
ISSN: 2192-8614
DOI: 10.1515/nanoph-2023-0704
Popis: A parabolic potential that confines charge carriers along the growth direction of quantum wells semiconductor systems is characterized by a single resonance frequency, associated to intersubband transitions. Motivated by fascinating quantum optics applications leveraging on this property, we use the technologically relevant SiGe material system to design, grow, and characterize n-type doped parabolic quantum wells realized by continuously grading Ge-rich Si1−x Gex alloys, deposited on silicon wafers. An extensive structural analysis highlights the capability of the ultra-high-vacuum chemical vapor deposition technique here used to precisely control the quadratic confining potential and the target doping profile. The absorption spectrum, measured by means of Fourier transform infrared spectroscopy, revealed a single peak with a full width at half maximum at low and room temperature of about 2 and 5 meV, respectively, associated to degenerate intersubband transitions. The energy of the absorption resonance scales with the inverse of the well width, covering the 2.5–5 THz spectral range, and is almost independent of temperature and doping, as predicted for a parabolic confining potential. On the basis of these results, we discuss the perspective observation of THz strong light–matter coupling in this silicon compatible material system, leveraging on intersubband transitions embedded in all-semiconductor microcavities.
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