forming a direct-silicon-bonded (DSB) bilayer comprising an upper single-crystal Si layer having a first surface orientation disposed on a lower single-crystal Si layer having a second surface orientation different from the first surface orientation;

selecting a plurality of first Si bilayer regions and a plurality of second Si bilayer regions, wherein said upper single-crystal Si layer will retain its original first surface orientation in said first bilayer regions and undergo an orientation change to a second surface orientation in said second bilayer regions;

forming a trench isolation around said first and second Si bilayer regions to produce isolation-bordered first and second Si bilayer regions;

amorphizing said first-orientation upper single-layer crystal Si layer in said second Si bilayer regions to form localized amorphized regions while leaving at least some of said second-orientation lower-single crystal Si layer in said second Si bilayer regions crystalline; and

melting said localized amorphized regions and recrystallizing them to said second surface orientation using said second-orientation lower-layer Si in said second bilayer regions as a template, wherein process conditions used to effect said melting and recrystallization are selected to avoid any orientation change in said first bilayer regions,

wherein said first and second surface orientations of said upper and lower Si layers of said DSB bilayer are selected from the group including (110) and (100),

wherein said DSB bilayer comprises a single-crystal Si layer having a (110) surface orientation directly bonded to an underlying Si-on-insulator substrate layer having a (100) surface orientation,

wherein said amorphizing comprises ion implantation,

wherein said melting and recrystallizing comprises laser irradiation with one or more pulses of laser irradiation having pulse lengths in a range from about 10 ns to about 200 ns,

wherein said laser irradiation has a wavelength in a range from about 190 to about 400 nm and a fluence in a range from about 0.1 to about 3 J/cm², and

wherein said laser irradiation further comprises:

forming antireflection and/or absorber layer coatings on substrate surfaces to be irradiated prior to laser irradiation; and

removing said antireflection and/or absorber layer coatings after said laser irradiation.