Abstract: Methods for cleaving semiconductor structures formed on c-face sapphire substrates are disclosed. An exemplary method includes forming at least one III-V nitride layer on the top c-face of a c-face sapphire substrate. A line of weakness is formed on the bottom c-face of the c-face sapphire substrate in the a-plane direction of the c-face sapphire substrate. A force is applied to the bottom c-face to cleave the c-face sapphire substrate along the line of weakness in the a-plane direction, and to form a cleaved facet along an m-plane of each III-V nitride layer. The III-V nitride layers can be included in laser diodes and other light-emitting devices.