Number of Quantum Well(s) Effects on GaN-Based VCSELs


Advanced numerical simulation program was used to analyze the performance of GaNbased vertical cavity surface emitting laser (VCSEL) with single, double and triplequantum well(s) as active region. It was found that numbers of quantum well (QW)variation inside the active region is the most critical factor on the VCSEL performance.The lowest threshold current and highest in both the slope efficiency and differentialquantum efficiency were observed when the well number is double (DQWs) at 415nm VCSEL. This is ascribed to that for single quantum well (SQW), some of the gainbegin to escape before lasing is achieved while for triple quantum wells (TQWs) whileare separated by many thick barriers, then transport carriers between wells will beinefficient. As a result, a non-uniform carrier distribution may result.