Dresden 2026 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 33: Nitrides I – Growth and fabrication

HL 33.4: Talk

Wednesday, March 11, 2026, 17:15–17:30, POT/0006

In-situ fabrication of In_0.3Ga_0.7N pseudo-substrates on GaN (0001) templates via a three-step protocol in plasma-assisted molecular beam epitaxy — •Huaide Zhang, Aidan Campbell, Jingxuan Kang, Jonas Lähnemann, Oliver Brandt, and Lutz Geelhaar — Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, 10117, Berlin, Germany

The considerable lattice mismatch between GaN and InN introduces significant strain into (In,Ga)N epitaxial layers grown on GaN templates. This strain impedes the incorporation of In and induces a strong piezoelectric field in (In,Ga)N/GaN quantum wells, which diminishes the internal quantum efficiency. Furthermore, the accumulated strain can prompt plastic relaxation of the lattice, generating additional threading dislocations. The high In content required for (In,Ga)N-based light-emitting diodes (LEDs) operating in the amber/red spectral range necessitates, hence, a substrate with an adjusted lattice constant. In this work, we present a three-step growth method for fabricating a highly relaxed In_0.3Ga_0.7N pseudo-substrate directly on GaN(0001) templates which is conducted entirely within a plasma-assisted molecular beam epitaxy system. In contrast to other approaches, our method does not require any ex-situ patterning, providing thus advantages in terms of scalability and cost. The resulting structure demonstrates superior characteristics in key properties, including In content, degree of strain relaxation, and surface smoothness compared to existing alternatives.

Keywords: molecular beam epitaxy; III-nitride; (In,Ga)N pseudo-substrate