Resonant cavity light emitting diodes with two single quantum wells of different widths

Resonant cavity light emitting diodes containing two single quantum wells of different well width were fabricated. The quantum wells, consisting of GaAs with AlGaAs barriers, were placed in separate antinodes of the optical emission mode in a Fabry–Perot cavity whose optical length is twice that of the resonant wavelength. For low forward bias currents, the emission from the wider quantum well is resonant with the cavity. For larger forward bias currents, the emission shifts to longer wavelengths due to an increase in the device temperature. The narrower single quantum well then becomes resonant with the cavity. Using the double quantum well structure, high output powers and high directivity are obtained for a wide range of forward bias current.