Broad-band light-emitting diode for 1.4-2.0 μm using variable-composition InGaAs quantum wells

We describe a novel broad-band light-emitting diode employing InGaAs quantum wells with different bandgaps. The device structures were grown by molecular-beam epitaxy on InP substrates and consist of three In/sub x/Ga/sub 1-x/As quantum wells (x=0.4, 0.53, and 0.66) imbedded in the p-doped region of an InAlAs p-n junction diode. Electrons injected into the p-region are captured into the wells and recombine with holes to produce radiation at the three bandgap wavelengths. Broad-band emission over a large wavelength range (1.4-2.0 μm) is easily achieved with this approach. These novel solid-state sources have a variety of potential applications, for example, in miniature spectrometer and sensor systems."