Fabrication and carrier transport properties of Si quantum dots/SiO2 multilayer films on Si substrate

Si quantum dots (Si-QDs)/SiO2 multilayer films have been fabricated on Si substrate, and the carrier transport properties of heterojunctions consisting of Al:Si/SiO2:Si:Al are studied. The current density-voltage curves show that high density Si-QDs lead to higher current density and rectifying ratio. The carrier transports in the forward voltage are controlled by Ohmic resistance model, tunneling and recombination limited current (TRLC) model, and space-charge limited current (SCLC) model, respectively. The TRLC is quenched by hydrogen passivation, while the SCLC-limited carrier transport process becomes the main carrier transport mechanism, and a 7.6 times current density enhancement is obtained. It suggests that the SCLC-limited model is more effective for carrier transport in the studied device.