Precise determination of polarization fields in c-plane GaN/Al x Ga1-x N/GaN heterostructures with capacitance–voltage-measurements

Norman Susilo, Marcel Schilling, Michael Narodovitch, Hsin-Hung Yao, Xiaohang Li, Bernd Witzigmann, Johannes Enslin, Martin Guttmann, Georgios G. Roumeliotis, Monir Rychetsky, Ingrid Koslow, Tim Wernicke, Tore Niermann, Michael Lehmann, Michael Kneissl

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Due to changes in the spontaneous and piezoelectric polarization, AlGaN/GaN heterostructures exhibit strong polarization fields at heterointerfaces. For quantum wells, the polarization fields lead to a strong band bending and a redshift of the emission wavelength, known as quantum-confined Stark effect. In this paper the polarization fields of thin AlGaN layers in a GaN matrix were determined by evaluating the changes in the depletion region width in comparison to a reference sample without heterostructure using capacitance–voltage-measurements. The polarization fields for Al0.09Ga0.91N (0.6 ± 0.7 MV cm−1), Al0.26Ga0.74N (2.3 ± 0.6 MV cm−1), Al0.34Ga0.66N (3.1 ± 0.6 MV cm−1), Al0.41Ga0.59N (4.0 ± 0.7 MV cm−1) and Al0.47Ga0.53N (5.0 ± 0.8 MV cm−1) heterostructures were determined. The results of the field strength and field direction of all samples are in excellent agreement with values predicted by theory and a capacitance–voltage based Poisson-carrier transport simulation approach giving experimental evidence for a nonlinear increasing polarization field with Al-concentration.
Original languageEnglish (US)
Pages (from-to)SCCB08
JournalJapanese Journal of Applied Physics
Issue numberSC
StatePublished - Apr 23 2019

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): BAS/1/1664-01-01, URF/1/3437-01-01, REP/1/3189-01-01
Acknowledgements: This work was supported by the German Federal Ministry of Education and Research (BMBF) within the Advanced UV for Life project and by the Deutsche Forschungsgemeinschaft (DFG) within the Collaborative Research Centre Semiconductor Nanophotonics (SFB 787). Part of this work was also co-funded by the Erasmus+ programme of the European Union. The KAUST authors acknowledge the support of KAUST Baseline BAS/1/1664-01-01, KAUST CRG URF/1/3437-01-01, and GCC REP/1/3189-01-01.


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