Method of producing image display unit

A method of producing light emitting devices, the method comprising the steps of:

• forming an array of light emitting devices on an upper surface of a sapphire substrate, the sapphire substrate having an exposed back surface that is opposite to the upper surface, the forming of the array of light emitting devices including
• growing a gallium nitride based first conductive type cladding layer on the sapphire substrate,
• growing an active layer on the first conductive type cladding layer, and
• growing a second conductive type cladding layer on the active layer;
• dividing the array of light emitting devices into a plurality of individual light emitting devices by forming separation grooves through the first conductive type cladding layer, the active layer and the second conductive type cladding layer to separate peripheries of respective individual light emitting devices from each other, wherein a depth of the separation grooves is sufficient to allow the upper surface of the sapphire substrate to be exposed through the light emitting devices;
• and
• irradiating an entire exposed back surface of the sapphire substrate with an energy beam to decompose a portion of the gallium nitride in the first conductive type cladding layer into nitrogen gas and metal gallium, thereby reducing a bonding force between the sapphire substrate and the first conductive type cladding layer of the light emitting devices;
• and
• peeling the sapphire substrate as a whole from each of the individual light emitting devices.