摘要
Selection of a proper supercooled temperature to grow an Al 0.7 Ga 0.3 As window layer onto an as-grown In 0.5 P active layer on a GaAs substrate has resulted in an improve device performance of Al 0.7 Ga 0.3 As/In 0.5 Ga 0.5 P single heterostructure light-emitting diodes. The transition width at the AlGaAs-InGaP interface is drastically reduced from 750 Å to a minimum value of 200 Å as the supercooled temperature of the AlGaAs melt was increased from 4 to 8°C. The light-emitting diode fabricated from this heterostructure shows a very small reverse leakage current of less than 1x10 -6 Å prior to breakdown and a forward-bias turn-on voltage of 1.50 V with an ideality factor of 1.64. The narrowest full width at half maximum of 160 Å at 20 mA measured by room-temperature electroluminescent spectra and the strongest light output power of 400 μW at 100 mA are obtained when the AlGaAs layer was grown with this optimized supercooled temperature of 8°C. The external quantum efficiency of 0.3% is twice higher than that previously reported. © 1991.