Charge-storage Effect of Vertically Stacked InAs Nanodots Embedded in Al0.5Ga0.5As Matrix

Abstract

In this paper we describe the memory effect of vertically stacked InAs nanodots in the barrier layer of an Al0.5Ga0.5As/GaAs field-effect (FE) structure, by comparing this effect with that of single-layer InAs nanodots in the same FE structure. These FE structures are grown by molecular beam epitaxy, and Stranski-Krastanow islands are used for the InAs nanodots. The charge-storage effect of the nanodots is analyzed by capacitance–voltage (C–V) measurement and results in a hysteresis loop caused by stable electron trapping at nanodot potentials. The amount of “net” charge surviving at the stacked nanodots at 300 K is estimated to be ∼ 14 nC/cm2, whereas that at the single-layer nanodots is nearly zero. These C–V characteristics are in good agreement with photoluminescence properties.