Competition between quantum‐confined Stark effect and free‐carrier screening effect in AlGaN/GaN multiple quantum wells

Abstract

The competition between the quantum‐confined Stark effect (QCSE) and the free‐carrier screening effect in AlGaN/GaN multiple quantum wells (MQWs) has been investigated by time‐resolved photoluminescence (PL) measurement. AlGaN/GaN MQWs is a promising material for the next‐generation ultraviolet light‐emitting diodes and laser devices. The large changes in the PL energy and the decay time are observed with changing carrier density. We show that the energy shift and the change in decay time are explained well by the free‐carrier screening effect that compensates for the internal electric field. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Screening of the quantum-confined Stark effect in AlN/GaN nanowire superlattices by germanium doping

“…22 . Experimentally, screening by photoexcited carriers after excitation with different excitation powers was observed in Al x Ga 1-x N/GaN QWs [23][24][25] as well as in AlN/GaN quantum dots (QDs) 26,27 .…”

Photocurrent readout and electro-optical tuning of resonantly excited exciton polaritons in a trap

“…The parameter used for the effective build-in potential V bi = 0.7 V at this given laser power is smaller than the theoretically expected build-in potential V bi ∼ 1.3 V. The deviation can be caused by several effects such as screening of intracavity and intra-QW electric field [27,28] or density dependent effects such as polariton-polariton interaction and bleaching of strong coupling. Consequently, we repeated this bias-series analysis for successive lower laser powers and found a closer value of V * bi ∼ 1.19 V for the undisturbed system by extrapolation of the phenomenological parameters.…”