title: Narrow intersubband transitions in n-type Ge/SiGe multi-quantum wells: control of the terahertz absorption energy trough the temperature dependent depolarization shift.
abstract: In this paper we present a detailed study of the intersubband absorption occurring between electron states confined in strained Ge multi-quantum wells as a function of the temperature. The high structural quality of the samples is reflected by the very narrow absorption line-shape constant with temperature. We observe a temperature driven charge transfer occurring between the ground and the first excited subband which, in turn, induces a change in the depolarization shift and consequently in the energy of the absorbance peak. The experimental observations are well accounted for by a multi-valley k·p model.
authors.affiliation: Dipartimento di Fisica E Amaldi, Università di Roma Tre, via Vasca Navale 84, I-00146 Roma, Italy.
authors.forename: M
authors.initials: M
authors.lastname: De Seta
authors.forename: G
authors.initials: G
authors.lastname: Capellini
authors.forename: M
authors.initials: M
authors.lastname: Ortolani
authors.forename: M
authors.initials: M
authors.lastname: Virgilio
authors.forename: G
authors.initials: G
authors.lastname: Grosso
authors.forename: G
authors.initials: G
authors.lastname: Nicotra
authors.forename: P
authors.initials: P
authors.lastname: Zaumseil