Dresden 2026 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 26: Poster II

HL 26.13: Poster

Wednesday, March 11, 2026, 09:30–11:30, P1

Impact of Al containing nucleation layers on Si(100)/GaP heterointerface — •Kai Daniel Hanke¹, Angieszka Paszuk^1,2, Peter Kleinschmidt¹, and Thomas Hannappel¹ — ¹Technische Universität Ilmenau, Fundamentals of Energy Materials, Ilmenau, Germany — ²Technische Universität Ilmenau, BMFTR Junior Research Group PARASOL, Ilmenau, Germany

Monolithically grown III-V-on-silicon (100) tandem solar cells show great promise for applications such as direct solar water splitting. A critical interface in these devices is the Si/GaP heterointerface, at which defects originate and subsequently propagate through the entire III-V epitaxial stack. Minimizing defect formation at this initial interface is therefore essential for achieving high-efficiency water-splitting performance. The use of TMAl during the pulsed nucleation of the GaP layer has previously been shown to lower defect densities, particularly stacking faults, stacking-fault pyramids (SF/SFP), and threading dislocations (TDs). In this study, we investigate the effect of TMAl on the formation of SF/SFP and on the density of TDs. We further analyze how TMAl modifies the interfacial energetic band alignment using X-ray photoelectron spectroscopy, and study its impact on surface anisotropy and interface-related optical transitions by low-temperature reflection anisotropy spectroscopy. Defect densities are quantified by electron channeling contrast imaging, a scanning electron microscopy technique that exploits electron channeling at an acceleration voltage of 30 kV.

Keywords: III-V-on-Si; GaP/Si Heterointerface; MOCVD; Optical Spectroscopy; ECCI