A method comprising: providing at least one first diamond film comprising polycrystalline diamond, e.g., nanocrystalline or ultrananocrystalline diamond, disposed on a substrate, wherein the first diamond film comprises a surface comprising diamond asperities and having a first diamond film thickness, removing asperities from the first diamond film to form a second diamond film having a second diamond film thickness, wherein the second thickness is either substantially the same as the first thickness, or the second thickness is about 100 nm or less thinner than the first diamond film thickness, optionally patterning the second diamond film to expose substrate regions and, optionally, depositing semiconductor material on the exposed substrate regions, and depositing a solid layer on the second diamond film to form a first layered structure. Applications include for example dielectric isolation in the semiconductor industry, as well as surface acoustic wave devices, scanning probe microscope, and atomic force microscope devices.