Electronic properties of a single heterojunction in InSb/InAs quantum dot system

We report on electronic transport properties of a single InSb quantum dot free-standing on the surface of a binary InAs matrix. The samples under study were grown by liquid phase epitaxy method. Characterisation of the sample surface was performed using atomic force microscopy (AFM). Uniform high-density (1 × 1010 cm−2) coherent InSb quantum dots with a height of 3-4 nm and a diameter of 13-18 nm were obtained at T = 430 °C. It was established that the sample surface has been covered by 3 nm-thick oxide layer in ambient environment at room temperature. Unique method of measurement of local tunnel transport across a type II broken-gap InSb/InAs heterojunction was proposed and developed. Electrical characteristics were measured in a contact mode with average force F = 75 nN that is enough to get repeatable I-V characteristics through the InSb oxide layer and to avoid destruction of the heterostructure. I-V characteristics of the single uncapped InSb quantum dot were for the first time obtained.

► We studied transport properties of a InSb QDs free-standing on the InAs surface. ► I-V characteristics of InSb/InAs QD system were for the first time obtained. ► Unique AFM method of local transport study without destruction of the sample surface.