Process for making island arrays

A method of forming an array of features comprising:

• (a) depositing a film of a soluble solid onto a surface of a hydrophilic substrate;
• (b) exposing the film to solvent vapour so that the film reorganises into an array of discrete hemispherical islands on the surface;
• (c) depositing a film of a resist material over the surface by directing a vapour stream of resist material at a grazing angle of incidence to the surface;
• (d) removing the hemispherical structures together with their coating of resist leaving a resist layer with an array of holes corresponding to the islands;
• and
• (e) subjecting the resulting structure to an etching process so as to form a well at the position of each hole.

A method of forming a crystalline heterostructure comprising two component materials having different lattice structures, in which the materials are arranged to contact each other via a plurality of discrete regions, the method comprising the steps of:

• (a) forming a layer of the first material;
• (b) forming an insulating layer on the surface of the first material so as to provide a hydrophilic substrate;
• (c) depositing a film of a soluble solid onto a surface of the hydrophilic substrate;
• (d) exposing the film to solvent vapour so that the film reorganises into an array of discrete hemispherical islands on the surface;
• (e) depositing a film of a resist material over the surface;
• (f) removing the hemispherical structures together with their coating of resist leaving a resist layer with an array of holes corresponding to the islands;
• (g) subjecting the resulting structure to an etching process so as to form a well at the position of each hole;
• and
• (i) growing crystals of the second material on the first material in the regions exposed by the holes so as to form an island at the position of each hole;
• wherein said two component materials are both metals.

A method of forming a crystalline heterostructure comprising two component materials having different lattice structures, in which the materials are arranged to contact each other via a plurality of discrete regions, the method comprising the steps of:

• (a) forming a layer of the first material;
• (b) forming an insulating layer on the surface of the first material so as to provide a hydrophilic substrate;
• (c) depositing a film of a soluble solid onto a surface of the hydrophilic substrate;
• (d) exposing the film to solvent vapour so that the film reorganises into an array of discrete hemispherical islands on the surface;
• (e) depositing a film of a resist material over the surface;
• (f) removing the hemispherical structures together with their coating of resist leaving a resist layer with an array of holes corresponding to the islands;
• (g) subjecting the resulting structure to an etching process so as to form a well at the position of each hole;
• and
• (i) growing crystals of the second material on the first material in the regions exposed by the holes so as to form an island at the position of each hole;
• wherein at least one of the two component materials is a metal compound comprising MaAs, MnSb, NiMnSb, PtMaSb, CuMnSb, LuPdSb, CO2MnGe, or CrO2.