Fabrication of 3D quantum dot array by fusion of biotemplate and neutral beam etching II: Application to QD solar cells and laser/LED

We investigated the controllable range of bandgap energy, E_gand optical absorption characteristic of silicon quantum nanodisks (QNDs) formed by a top-down method described in previous chapter, which enables precise control of geometrical parameters. By embedding by Silicon Carbides, the wave function of the QNDs overlaps each other, and a wide miniband was formed, which enhance only the photon absorption but carrier transport in the stacked QNDs. The high optical absorption and conductivity properties were verified by fabricating p-i-n solar cells with Si-NDs, and efficient carrier generation and high electrical conductivity in our Si-ND structure were surely clarified. The top-down process was also applied to form quantum dots photonic devices based on III-V compound semiconductors. We fabricated GaAs nanodisks (NDs) with a diameter of sub-20 nm. The GaAs NDs were embedded with AlGaAs regrown by metal organic vapor phase epitaxy. Light emitting diodes were fabricated using the NDs, exhibiting a narrow spectral width of 38 nm with high-intensity as a result of small size deviation of NDs and superior quality of GaAs/AlGaAs surface formed by neutral beam etching.