DESIGN AND PHOTOLUMINESCENCE STUDY ON A MULTIQUANTUM BARRIER

We have optimized the structure of a multiquantum barrier (MQB) by examining possible choices of well and barrier thickness and pair number for a visible AlGaInP laser in the 630 nm wavelength range. We confirmed that an effective potential barrier can be two times as high as a classical potential barrier U0 by introducing the MQB composed of relatively thin (Al(x)Ga1-x)0.5In0.5P(x = 0.2)-(Al(x)Ga1-x)0.5In0.5P(x = 0.7) superlattices. The actual potential barrier height under biased conditions is shown to be at least larger than 50 meV, considering the variation of Fermi level changes in the MQB region. This may contribute to higher temperature CW operation when introduced into visible AlGaInP lasers. By photoluminescence (PL) measurement, we have also experimentally verified the effect of electron-wave confinement of a GaAs-AlGaAs MQB. We observed a weak saturation in PL excitation power dependence and less sensitive temperature dependence. These could be due to the increase of potential barrier height, and show a superior carrier confinement of MQB.