Two-dimensional arrays of self-organized Ge islands obtained by chemical vapor deposition on pre-patterned silicon substrates

Ordered arrays of Ge islands on a Si( 100) surface were obtained using interference lithography for pre-patterning and subsequent growth by chemical vapor deposition (CVD). The patterns represent arrays of holes etched 10-30 nm deep into the Si substrate, with a periodicity of 280-320 nm. The holes were fabricated using reactive ion etching. Prior to island growth, a Si buffer layer was grown for optimizing the shape of the patterns. The samples were analyzed using atomic force microscopy and photoluminescence. It was found that Ge island arrays deposited on patterned substrates have a narrower size distribution and a more intense photoluminescence than islands on non-patterned areas. Parameters controlling the perfection of ordered arrays of islands are discussed.