The factors which influence the ultimate output power of semiconductor laser are analyzed. The aluminum-free two-quantum-well semiconductor laser which wavelength is 940 nm is made by MOCVD. As a result, the peak wavelength of the aluminum-free two-quantum-well semiconductor laser is 940 2 nm, the full-width-half-maximum (FWHM) is 2 nm, the continuous output power is 10 W, and the incremental efficiency is 1 09 W/A.