Fabrication and characterization of ordered GeSi nanoislands on Si (001) substrates
Ordered GeSi nanoislands were fabricated in combination of self-assembly and nanosphere lithography on Si (001) substrates. Well ordered pits in a hexagonal lattice on Si (001) substrates are readily obtained via nanosphere lithography. The preferential nucleation of GeSi nanoislands in the pits results in laterally ordered nanoislands on such prepatterned Si (001) surface during Ge deposition. Multilayer GeSi nanoislands separated by thin Si spacer layers were also realized. The vertical alignment of nanoislands along the growth direction can give rise to three-dimensionally ordered nanoislands or nanoisland crystal. To explore the optoelectronic properties of ordered nanoislands, A Si p-i-n diode embedded with multilayer ordered GeSi nanoislands were fabricated. Photoluminescence of the samples with multilayer GeSi nanoislands were studied.