Self-aligned nanolenses with multilayered Ge/SiO2 core/shell structures on Si (001)

Selective etching of multilayered Ge-quantum-dot/Si-spacer has been used to fabricate stacked Ge@SiO2 nanolenses with the ability to filter and focus 1.5 mu m light. These lenses have potential for use as Si-compatible photodetector materials for telecommunications. The left figure is a schematic sketch of the nanolenses and the right figure is a transmission electron microscopy image of the lenses.