T. Ishikawa, S. Kohomoto and K. Asakawa.

The Femtosecond Technology Research Association (FESTA)

5-5- Tohkodai, Tsukuba, Ibaraki 300-2635, Japan.

Semiconductor nanostructures, such as quantum dots (QDs) or quantum wires (QWRs), are very promising for future optoelectronic device applications. To realize the expected excellent device performances, the sites and sizes of the nanostructures must be fully controlled. For this purpose, we have developed through-UHV (in situ) processing technology by combining in situ electron beam (EB) patterning and self-organized MBE growth [1]. By this method, for example, small, shadow holes (diameter, 100 nm; depth, 1 to 5 nm) were formed on GaAs surfaces, and then a few monolayers of InAs were supplied to form QDs. AFM observations revealed that the resulting QDs were selectively formed in the holes without any QD formation in the flat region between the holes because of preferential nucleation of InAs growth in the holes. These results demonstrate the usefulness of the in situ patterning and self-organizing growth approach in realizing arbitrarily designed nanostructures since it enables defining ultrafine patterns with high quality.

This work was supported by NEDO within the framework of the Femtosecond Technology Project.

[1] T. Ishikawa et al., Appl. Phys. Lett., 73 (1998) 1712.