We have already developed a uniform silicon-based two-dimensional quantum dot superlattice (2D QDSL) (i.e., 2D array of Si nanodisks) on the x-y plane with high-density nanodisks (NDs) and controllable size and spacing between NDs. To integrate more nanodisks in the third dimension (z-axis), a new stacked nanodisk (S-ND) has been developed by using thin film deposition, bio-template and advanced alternate etching. The SND structure comprises of two NDs connected vertically by coupling a tunnel junction (TJ). The scanning transmission electron microscopy image clearly revealed the stacked structure. The quantum confinement of S-ND was confirmed by observing the Coulomb staircase at room temperature. Tunneling current could be controlled by changing TJ thickness. By simply changing the ND thickness, band gap energy (Eg) could be controlled. These characteristics of the quantum effect and Eg play important roles in QDSL solar cells.
ASJC Scopus subject areas
- Physics and Astronomy(all)