Sb-mediated Ge quantum dots in Ti–oxide–Si diode: negative differential capacitance

Abstract

The negative differential capacitance (NDC) effect is observed on a titanium–oxide–silicon structure, formed on n-type silicon with embedded germanium quantum dots (QDs). The Ge QDs were grown by an Sb-mediated technique. The NDC effect was observed for temperatures below 200 K. We found that approximately six to eight electrons can be trapped in the valence band states of Ge QDs. We explain the NDC effect in terms of the emission of electrons from valence band states in the very narrow QD layer under reverse bias.

p-TlGaSeS/n-BN heterojunction as a microwave filter and as a photovoltaic device

“…The NDC effect was also detected in titanium-oxide-silicon quantum dots. The phenomenon was assigned to the emission of electrons from the valence-band states in very narrow quantum dot layer under reverse biasing conditions [12]. The NDC effect that is observed in the p-n heterojunctions was also previously observed in p-MgO/ n-InSe heterojunction and was ascribed to the increments in the polarization and the availability of more carriers in the structure and/or due to a nonmonotonic time derivative of the transient current at a particular applied voltage (typical tunneling diode behavior) [13].…”