Impact of Carrier Transport on Aquamarine--Green Laser Performance

We studied the carrier transport phenomena of the multiple-quantum-well (MQW) active region and their impact on the performance of aquamarine and green laser diodes (LDs) grown on polar and semipolar planes. The ballistic carrier transport mechanism was found to be dominant in the MQW region. For the $c$-plane, because of the high hole capture probability and slow escape rate, mainly the quantum wells (QWs) positioned close to the p-side are electrically pumped. The optical loss induced by the underpumped QWs further away from the p-side leads to significantly higher laser threshold current density and a longer lasing wavelength with increased number of QWs. These effects are not significant for semipolar LD structures.