The effects of quantum wells number and the built-in polarization on the performance of quaternary AlInGaN UV laser diode

The performance of quaternary Al0.08In0.08Ga0.84N multi-quantum well (MQW) laser diodes (LDs) using the simulation program of Integrated System Engineering Technical Computer Aided design (ISE TCAD) was studied. The simulation results show that the low threshold current, high output power and slope efficiency can be obtained when the quantum wells number is 4. Although, the fourth quantum well which placed in the right side (n-side) of the active region has a negative value of optical gain this means that the optical gain does not occur in this quantum well of laser structure. However, high external differential quantum efficiency (DQE) inside the active region was also observed. Optical gain and intensity were increased when the numbers of quantum wells increase reached 4. The built-in electric field effect inside the quantum well leads to the reduction of the overlap integral between the electrons and holes by separating their wave function was included. As well as, Al0.25In0.08Ga0.67N electron blocking layer (EBL) employed to enhance the performance of Al0.08In0.08Ga0.84N MQW LDs by increasing the optical confinement factor (OCF) inside the quantum wells.