Description:
Nanometer-scale selective area growth of ZnS and ZnSe was investigated. The growth was performed by metalorganic molecular-beam epitaxy (MOMBE) on a carbon-masked GaAs substrate at temperatures ranging from 350°C to 390°C. For pattern sizes larger than several hundred of nanometers, a good selectivity and uniformity of the grown structures were observed, but for mask opening sizes less than ∼100 nm, uniformity of the grown structures was not satisfactory. This situation was identified as originating from the poor nucleation and to be intrinsic to the nanometer-scale selective area growth. In order to resolve this issue, the conditions for enhancing the nucleation were studied. The replacement of conventional As–Zn bonding with Ga–S or Ga–Se bonding at the heterointerface proved to be effective for enhancing the nucleation probability, and thus, the uniformity of the grown nanostructures, while preserving good selectivity.