Frankerl, Christian;
Hoffmann, Marc P.;
Nippert, Felix;
Wang, Heng;
Brandl, Christian;
Tillner, Nadine;
Lugauer, Hans-Jürgen;
Zeisel, Roland;
Hoffmann, Axel;
Davies, Matthew J.
Challenges for reliable internal quantum efficiency determination in AlGaN-based multi-quantum-well structures posed by carrier transport effects and morphology issues
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Medientyp:
E-Artikel
Titel:
Challenges for reliable internal quantum efficiency determination in AlGaN-based multi-quantum-well structures posed by carrier transport effects and morphology issues
Beteiligte:
Frankerl, Christian;
Hoffmann, Marc P.;
Nippert, Felix;
Wang, Heng;
Brandl, Christian;
Tillner, Nadine;
Lugauer, Hans-Jürgen;
Zeisel, Roland;
Hoffmann, Axel;
Davies, Matthew J.
Beschreibung:
<jats:p>We report on a systematic study of the determination of the internal quantum efficiency (IQE) in AlGaN-based multiple-quantum-well (MQW) structures using different optical evaluation methodologies and experimental conditions, in order to derive a standard set of measurement conditions for reliable IQE determination. Several potential sources of error that may distort the IQE obtained by optical measurements are discussed, such as carrier transport effects, excitation conditions failing to fulfill ideal resonance conditions, and morphology issues. A series of nominally identical AlGaN-based MQW structures is grown on an AlGaN layer separated by an AlN interlayer of varying thickness. The MQW structures are studied both by resonant and quasiresonant photoluminescence spectroscopy, and IQEs are determined via different commonly employed methods. The obtained values are shown to be significantly affected by the employed excitation conditions, as well as the evaluation techniques. In addition, growth morphology issues and carrier transport effects need to be considered in the interpretation of the measured data, with the latter being investigated in greater detail. The results emphasize the need for an appropriate choice of both experimental conditions and evaluation methodology in order to extract reliable and comparable IQE values.</jats:p>