The state of Zn diffusion at the hetero-interface of 660nm double-hetero light-emitting diodes was investigated by using the electron beam-induced current method. The p-n junction penetrated towards the n-cladding layer, as a result of Zn diffusion, when the carrier concentration of the p-active layer was greater than 1018/cm3. The distance between the hetero-interface and the p-n junction was related to the optical output and modulation band-width of a light-emitting diode. The dependence of the Zn effective diffusion coefficient upon the carrier concentration of the p-active layer and n-cladding layer was investigated. It was concluded that a suitable growth temperature for the active layer was about 850C.

M.Yoneda, Y.Nakamura, A.Tsushi, K.Ichimura: Japanese Journal of Applied Physics, 1993, 32[1-9A], 3770-4