Regensburg 2025 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 36: Materials and Devices for Quantum Technology II
HL 36.1: Vortrag
Mittwoch, 19. März 2025, 15:00–15:15, H13
High aspect ratio wurtzite GaAs nanowires as a platform for hexagonal SiGe — •Marvin Marco Jansen1, Wouter H.J. Peeters1, Marcel A. Verheijen1,2, and Erik P.A.M. Bakkers1 — 1Department of Applied Physics, Eindhoven University of Technology, Groene Loper 19, 5612AP Eindhoven, The Netherland — 2Eurofins Materials Science BV, High Tech Campus 11, 5656 AE Eindhoven, The Netherlands
One of the most promising pathway to create a silicon based laser is the recently developed hexagonal silicon germanium (hex-SiGe) shells around wurtzite (WZ) gallium arsenide (GaAs) nanowires (NWs) for which efficient direct band gap emission was shown. However, studies have highlighted the limitations of the core/shell NW system. A main challenge is the recently discovered aspect ratio limitation in WZ GaAs NWs ascribed to a dynamic variation of the growth conditions. Here, we report on the crystal phase control of GaAs NWs down to the monolayer regime opening up new pathways for superlattices as well as high aspect ratios GaAs NWs. To achieve this, Ga pulses are executed by momentarily halting the As supply, leading to an accumulation of Ga atoms within the catalyst particle. This process leads to the increase of the contact angle of the catalyst particle enabling a controlled transition from the WZ phase to the zinc blende (ZB), and then back to the WZ phase. By using the ZB inclusion as a marker during the growth process, we successfully carried out a detailed investigation into the evolution of the NW growth, considering its diameter, length, and the pulse frequency.
Keywords: GaAs; Nanowire; Crystal phase; SiGe