In-situ Er-doped GaN optical storage devices using high-resolution focused ion beam milling

High-density GaN:Er optical storage devices were fabricated with focused ion beam (FIB) milling techniques. In-situ Er-doped GaN films (1-1.5 μm thick) were grown on Si substrates. To "write" a bit, the GaN:Er film was selectively milled with a 30-keV Ga + FIB. Data retrieval is accomplished by upconversion emission at 535/556 nm upon 1-μm IR laser stimulation. Regions where the Er-doped GaN layer is completely removed (and do not emit) are defined as logic "0," while regions that are not milled (and do emit) are defined as logic "1." Data patterns with submicron bit size (or 100 Mb/cm 2 density) have been fabricated by FIB milling. Data written by this approach has a theoretical storage capacity approaching 10 Gbits/cm 2 .