Bulk single crystal gallium nitride and method of making same

A method of making a free-standing III-V nitride single crystal article, comprising:

• growing single crystal III-V nitride material, on and across a surface of a heterogeneous substrate having a diameter or corresponding dimension in an x,y plane of the surface that is at least 2.5 centimeters, to a thickness of at least 100 micrometers, by a vapor deposition process conducted at elevated growth temperature;
• and
• removing the heterogeneous substrate from the single crystal III-V nitride material grown to said thickness, while the single crystal III-V nitride material is at temperature within 300° C. of said elevated growth temperature and prior to cooling of said single crystal III-V nitride material to temperature more than 300° C. below said elevated growth temperature, to yield a free-standing III-V nitride single crystal article having a diameter or corresponding dimension in an x,y plane that is at least 2.5 centimeters, and is at least 100 micrometers in thickness.