Modulation Doping of Template-Defined InGaAs Nanowires

Templated semiconductor nanowires with strong spin-orbit interaction (SOI) are a scalable and versatile platform [1] to create and study novel quantum states of matter, such as helical states and spin helices, Majorana- and para-fermions. Modulation doping is a very well established technique to enhance mobility and control carrier concentration. Here, we report recent results on InGaAs nanowires with remote doping in the GaAs nanomembrane template grown via molecular beam epitaxy in a selective area growth approach [2]. By confining dopants near the top of the GaAs membrane and increasing the indium content, the process gives major improvements in mean free path and SOI. With a wrap-around top gate, the density was tuned down to full depletion. Using a split gate would make it possible to apply and tune an electric field, opening new avenues for investigating gate-controlled Rashba and Dresselhaus SOI.

[1] M. Friedl et al., Nano Lett. 18, 2666-2671 (2018)
[2] M. Friedl et al., Nano Lett. 20, 3577-3584 (2020)