InGaP/InGaAlP double-heterostructure and multiquantum-well laser diodes grown by molecular-beam epitaxy

Room-temperature continuous-wave (cw) operation is achieved in the MBE (molecular-beam epitaxy)-grown InGaP/InGaAlP double-heterostructure (DH) visible laser diodes with a threshold current of 110 mA. The lasing wavelength and threshold current density under pulsed operation are 666 nm and as low as 3.9 kA/cm2, respectively. This result is achieved by the introduction of H2 into the growth chamber during growth, the continuous growth from one layer to the next layer, and the introduction of a GaAs buffer layer. InGaP/InGaAlP quantum well structures are also grown. From photoluminescence measurements, the conduction-band discontinuity ΔEc is estimated to be 0.43 of the band-gap difference ΔEg. Furthermore, the multiquantum-well (MQW) structure is found to be stable under thermal treatment at temperatures as high as 750 °C. Room-temperature pulsed operation of InGaP/InGaAlP MQW laser diodes is achieved for the first time. The lasing wavelength is 658 nm with a threshold current density of 7.6 kA/cm2. cw operation is also achieved in the MQW laser diodes at −125 °C.