Growth and characterization of CaF2/Ge/CaF2/Si(111) quantum dots for resonant tunneling diodes operating at room temperature

Abstract

Resonant tunneling diodes were implemented on Ge quantum dots fabricated using Stranski–Krastanov growth mode on CaF2 matrix, lattice matched to Si(111) substrates. The negative differential conductance and conductance oscillations due to hole resonant tunneling through the zero-dimensional states of Ge quantum dots are clearly observed at room temperature. From the period of conductance oscillations, the energy separations between the states of the quantum dots with different sizes are estimated to be 40–50 meV (i.e., >kT=26 meV at T=300 K).