Dresden 2014 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 35: Poster I: Application of thin films; Focus session: Sensoric micro and nano-systems; Focus Session: Sustainable photovoltaics with earth abundant materials; Graphen (joint session with TT; MA; HL; DY; O); Ion and electron beam induced processes; Layer properties: electrical, optical, and mechanical properties; Magnetic/organic interfaces, spins in organics and molecular magnetism; Micro- and nanopatterning (jointly with O); Organic electronics and photovoltaics (jointly with CPP, HL, O); Thermoelectric materials

DS 35.45: Poster

Mittwoch, 2. April 2014, 17:00–20:00, P1

Transmission and optical properties of III-nitride multiple quantum wells and superlattices with disturbed periodicity — •Iglika Asenova and Evgenia Valcheva — Sofia University St. Kliment Ohridski, Faculty of Physics, 5 James Bourchier Blvd, 1164 Sofia, Bulgaria

The III-nitride semiconductors (AlN, GaN and InN) are object of a significant interest in the past years for they enable a wide range of innovative multiple layered nanosized systems and devices. Usually grown by MOCVD, the barrier periodic structures, such as superlattices and multiple quantum wells, sometimes exhibit a certain breach in their periodicity. In this study we will examine the 1 and 2 monolayer fluctuations in the barrier widths of III-nitride superlattices and multiple quantum wells and the effect the broken periodicity exerts upon the tunneling and the optical properties of the considered structures. Since in most cases the III-nitride structures are negatively doped, we restrain ourselves on examining the transmission coefficient in the conduction band only. Our calculations take account of the macroscopic internal polarization fields (spontaneous and piezoelectric) in the composing layers and the model we exploit is based on the envelope function approximation. Finally, we will compare our theoretical results with experimental data we have previously obtained.