Dresden 2014 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

HL: Fachverband Halbleiterphysik

HL 13: Nitrides: Optical characterization

HL 13.4: Vortrag

Montag, 31. März 2014, 12:00–12:15, POT 251

Valence band order in c-oriented wurtzite AlGaN layers — •Benjamin Neuschl¹, Jeffrey Helbing¹, Manuel Knab¹, Hannah Lauer¹, Tobias Meisch², Kamran Forghani², Ferdinand Scholz², and Klaus Thonke¹ — ¹Institute of Quantum Matter / Semiconductor Physics Group, University of Ulm — ²Institute of Optoelectronics, University of Ulm

Aluminum gallium nitride (AlGaN) is the key material system for semiconductor-based optical devices emitting in the ultraviolet spectral region of light. Until now, some fundamental properties such as the valence band structure are not safely explored yet for all compositions. Especially the symmetry of the topmost valence band has a major impact on the light extraction behavior of the device.

Different layers of c-oriented wurtzite AlGaN were grown by metalorganic vapor phase epitaxy, and investigated by means of temperature- and polarization-dependent photoluminescence and X-ray spectroscopy. Knowing the samples’ strain situation, we derive the valence band order, as a function of the relative amount of Al for a unified strain state. Subsequently, k· p theory allows the simulation of the strain-dependent valence band crossing. These fundamental results allow to design optimal light emitters for different emission wavelengths.