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HL: Fachverband Halbleiterphysik

HL 58: Nitrides: Preparation and characterization I

HL 58.8: Vortrag

Donnerstag, 19. März 2020, 11:45–12:00, POT 112

Capacitance-Voltage spectroscopy at room temperature of self-assembled GaN quantum dot ensembles under illumination — •Carlo Alberto Sgroi¹, Julien Brault², Jean-Yves Duboz², Peter Conrad¹, Arne Ludwig¹, and Andreas D. Wieck¹ — ¹Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, D-44780 Bochum, Germany — ²CNRS - CRHEA, Rue Bernard Grégory, 06560 Valbonne, France

We present capacitance voltage (CV) measurements under illumination at room temperature of charge-tunable self-assembled wurtzite GaN quantum dots (QDs) in an Al_xGa_1−xN matrix grown by MBE.

GaN and its alloys have excellent properties such as their thermal stability, high thermal conductivity and wide bandgap energies which make them an ideal candidate for next-generation GaN-based power devices and QD storage devices. Due to polarization and strain effects in wurtzite GaN/Al_xGa_1−xN heterostructure layers, the band structure is different where QDs and wetting layer (WL) are, respectively. Large electric fields and phonon processes promote charge transfer through the WL.

Performing CV spectroscopy on an AlGaN-Schottky diode structure with embedded GaN QDs, we observe a hysteresis effect in the charging and discharging of the QDs at room temperature. Under illumination of 395 nm, bandgap excitation of the QDs, we change the electron exchange mechanism and are able to remove the hysteresis effect completely.