THz Spectroscopy of Extremely Shallow Acceptors States in Ge/GeSi Multiple-Quantum-Well Heterostructures
V.Ya. Aleshkina, Y.V. Erofeevaa, V.I. Gavrilenkoa, A.V. Ikonnikova, D.V. Kozlova, O.A. Kuznetsova and D.B. Vekslerb
aInstitute for Physics of Microstructures, GSP-105, Nizhny Novgorod, 603950, Russia
bRensselaer Polytechnic Institute, Troy, NY, USA
Full Text PDF
Received: 22 08 2004;
New shallow acceptor magnetoabsorption lines in THz range have been discovered under bandgap photoexcitation in strained Ge/GeSi multiple-quantum-well heterostructures. It is shown, both theoretically and experimentally, that the resonant absorption results from the photoionization of A+-centers and from 1s→2p+-type transitions from the ground state of the barrier-situated A0-centers into excited states in the 1st and 2nd electronic subbands. The shallowest discovered ground acceptor states (EB≤0.5 meV) are attributed to the "barrier-spaced" acceptors (a hole bound with an acceptor ion in the neighboring Ge quantum well).
DOI: 10.12693/APhysPolA.107.137
PACS numbers:71.55.Cn, 76.90.+d, 78.67.De