(Invited) Processing and Characterization of High Density Si/Ge Quantum Dots for Electroluminescent Devices

Abstract

We have formed a double stack of a highly dense layer of Si quantum dots (Si-QDs) with Ge core on thermally-grown SiO2 by controling low pressure chemical vapor depositions of Si and Ge and remote plasma-enhanced oxidation, and characterized electroluminescence (EL) from the double stack through the Si substrate after making diodes with Al and Au top electrodes to the double stack formed on p- and n-Si(100), respectively. With application of 1kHz pulsed bias in the forward direction to the double-stacked Si-QDs with Ge core, EL signals peaked at ~0.83eV were observed irrespective of pulse height in the range of 3~5V. In addition to radiative recombination between higher order quantized states in the Ge core, the direct bandgap transition in Ge core may be involved in the EL signals.