Ion-induced interdiffusion of surface GaN quantum dots

Abstract

In the flourishing fields of quantum technology gallium nitride (GaN) quantum dots (QDs) have great appeal by providing high stability and room-temperature operation. Here, we report on the ion implantation of surface GaN QDs grown in the hexagonal crystal structure. An uncapped sample (S1) and two samples capped by 8ML (S2) and 16ML (S3) of AlN are subjected to a 100keV gallium (S1, S2) and a 210keV erbium (S3) ion beam. The fluence ranged from 5×1010cm−2 to 1×1015cm−2 (S1, S2) and from 5×1010cm−2 to 5×1013cm−2 (S3). QD characterization is performed by cathodoluminescence measurements at 77K and atomic force microscopy and scanning electron microscopy.Strong interdiffusion processes upon ion impact at the interfaces are evidenced leading besides other effects to a quenching of the quantum confined Stark effect. Moreover, a model for the QD morphology based on a fluence-dependent diffusion coefficient is developed.