Carrier mobilities of (001) cadmium arsenide films

Abstract

We investigate (001)-oriented films of the topological semimetal cadmium arsenide (Cd3As2) grown by molecular beam epitaxy on lattice-matched III–V AlxIn1−xSb buffer layers. Magnetotransport studies and analysis of thin film microstructures are used to determine the influence of dislocations on their carrier mobilities. We show that only a minority of the threading dislocations present in the buffer layers extend into the Cd3As2 films. Threading dislocations are shown to reduce the mobilities of carriers residing in the topological surface states, while bulk transport was unaffected by a change in the dislocation density across an order of magnitude. Thick (001) Cd3As2 films exhibit electron mobilities of up to 41 000 cm2 V−1 s−1 at 2 K. The results provide insights into the influence of extended defects on the transport properties of a prototype topological semimetal.