Coulomb blockade induced negative differential resistance effect in a self-assembly Si quantum dots array at room temperature

We report a Coulomb blockade induced negative differential resistance (NDR) effect at room temperature in a self-assembly Si quantum dots (Si–QDs) array (Al/SiO2/Si–QDs/SiO2/p-Si), which is fabricated in a plasma enhanced chemical vapor deposition system by using layer-by-layer deposition and in-situ plasma oxidation techniques. Obvious NDR effects are directly observed in the current–voltage characteristics, while corresponding capacitance peaks are also identified at the same voltage positions in the capacitance–voltage characteristics. The NDR effect in dot array, arising from the Coulomb blockade effect in the nanometer-sized Si–QDs, exhibits distinctive scan-rate and scan-direction dependences and differs remarkably from that in the quantum well structure in the formation mechanism. Better understanding of the observed NDR effect in Si–QDs array is obtained in a master-equation-based numerical model, where both the scan-rate and scan-direction dependences are well explained.