Using InAs quantum wells to navigate the Majorana parameter space

Although superconducting contacts laid down on self-assembled nanowires have produced impressive experimental results, the desire to build complex and scalable devices using Majorana modes leads us to want to develop lithographically defined nanowires. Our strategy is to deposit a superconducting layer in situ on an MBE-grown InAs 2DEG, and etch nanowires in subsequent microfabrication. This allows control over nanowire properties as well as the ability to vary the superconductor-semiconductor coupling strength in a precise manner. We plan to present measurements of both Nb coupled to an InAs 2DEG and nanowires fabricated out of two-dimensional InAs systems. We then discuss where these measurements put our system in the parameter space needed to observe the Majorana fermion, and propose a path forward.