Coherent Hole Transport in Selective Area Grown Ge Nanowire Networks.

Ramanandan, Santhanu Panikar; Tomić, Petar; Morgan, Nicholas Paul; Giunto, Andrea; Rudra, Alok; Ensslin, Klaus; Ihn, Thomas; Fontcuberta I Morral, Anna · Nano Lett · 2022

basic_science · Level V

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Abstract

Holes in germanium nanowires have emerged as a realistic platform for quantum computing based on spin qubit logic. On top of the large spin-orbit coupling that allows fast qubit operation, nanowire geometry and orientation can be tuned to cancel out charge noise and hyperfine interaction. Here, we demonstrate a scalable approach to synthesize and organize Ge nanowires on silicon (100)-oriented substrates. Germanium nanowire networks are obtained by selectively growing on nanopatterned slits in a metalorganic vapor phase epitaxy system. Low-temperature electronic transport measurements are performed on nanowire Hall bar devices revealing high hole doping of ∼10<sup>18</sup> cm<sup>-3</sup> and mean free path of ∼10 nm. Quantum diffusive transport phenomena, universal conductance fluctuations, and weak antilocalization are revealed through magneto transport measurements yielding a coherence and a spin-orbit length of the order of 100 and 10 nm, respectively.