Effect of Zn Diffusion on the Properties of AlGaAs Double-Hetero Light-Emitting Diodes

Abstract

The state of Zn diffusion on the heterointerface of 660 nm AlGaAs double-hetero (DH) light-emitting diodes (LEDs) was investigated by the electron-beam-induced current (EBIC) method. The p-n junction penetrates toward the n-cladding layer as a result of Zn diffusion when the carrier concentration of the p-active layer is greater than 1×1018 cm-3. The distance between the heterointerface and p-n junction was related to the optical output and modulation bandwidth of LEDs. For producing superior LEDs, it is important that the p-n junction coincides with the hetero interface or slightly penetrates into the n-cladding layer. The dependence of the Zn effective diffusion coefficient on the carrier concentration of the p-active layer and n-cladding layer was also investigated. Finally, it was determined that the suitable growth temperature of the active layer was around 850°C.