HIGH-FREQUENCY OPERATION OF HEAVILY CARBON-DOPED GA0.51IN0.49P GAAS SURFACE-EMITTING LIGHT-EMITTING-DIODES GROWN BY METALORGANIC MOLECULAR-BEAM EPITAXY

Single-heterostructure light-emitting diodes (LEDs) consisting of a wide band-gap N-Ga0.51In0.49P emitter and a heavily carbon-doped p-GaAs active layer have been grown by metalorganic molecular beam epitaxy. Trimethylgallium has been utilized to dope the GaAs active layer for a hole Concentration of 1.5 X 10(20) cm-3 in order to reduce the radiative lifetime of minority carriers in GaAs. The cw electroluminescent spectra of these LEDs indicate that the injection efficiency of the Ga0.51In0.49P/GaAs heterojunction is not degraded by carbon redistribution, even in the absence of an undoped spacer layer between the GaAs active layer and the Ga0.51In0.49P emitter layer. The transient optical response of the LEDs determines an optical 3 dB bandwidth in the range of 0.6-2.0 GHz. The external brightness of the carbon-doped LEDs is shown to be approximately a factor of 20 lower than that of double-heterostructure LEDs containing active layers more moderately doped with Be at 2 X 10(18) cm-3.