Quantum Dots for Memories

This chapter demonstrates the feasibility of a QD-based memory to replace today’s Flash and dynamic random access memory (DRAM). A novel memory concept based on QDs is presented, enabling very fast write times below picoseconds, only limited by the charge carrier relaxation time. A thermal activation energy of 710 meV for hole emission from InAs/GaAs QDs across an Al

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As barrier is determined by using time-resolved capacitance spectroscopy. A hole storage time of 1.6 seconds at room temperature is measured, three orders of magnitude longer than the typical DRAM refresh time. In addition, the dependence of the hole storage time in different III–V QDs on their localization energy is determined and a retention time of more than 10 years in (In)(Ga)Sb/AlAs QDs is predicted. Therefore, a future QD-based memory will show improved performance in comparison to both DRAM and Flash having fast write/read times and good endurance.