Observation of negative differential resistance from a Schottky-barrier structure embedded with Fe quantum dots

Abstract A Au/ZnS/Fe-quantum dots (QDs)/ZnS/n + -GaAs(1 0 0) Schottky-barrier structure containing five layers of spherical Fe QDs with diameter around 3 nm was fabricated by the molecular beam epitaxy technique. Its current–voltage ( I – V ) characteristics measured from 5 to 295 K display negative differential resistance (NDR) for temperature ⩽50 K, which is caused by the presence of Fe QDs. The highest peak-to-valley current ratio obtained at 5 K is as high as 15:1. Staircase-like I – V characteristic was also observed at low temperature in some devices fabricated from this structure. Possible mechanisms that can account for the observed unusual I – V characteristics in this structure were discussed.