Abstract
InP/AlGaInP QD laser diodes with various cavity lengths grown on GaAs substrate were synthesized by (MOVPE) technique. L-I characteristics at various temperatures (190–390K) were measured for InP/AlGaInP QD laser diodes to investigate the effect of the various stripe cavity length on threshold current density and characteristic temperature. It is found that the threshold current increases with temperature, reaches a peak, then drops as temperature increases, before it increases again at temperatures over 300K due to carrier redistribution in the quantum dot states with temperature. It is found also that the threshold current density decreases with increasing cavity length due to the increasing threshold gain with the cavity length. However, as the cavity length increases beyond certain length, the rate of the decrease of the threshold current with cavity length decreases. One important finding is that the characteristic temperature of threshold current decreases significantly with the cavity length at the operating temperature range from 190K to 360K.
•Synthesis of the InP/AlGaInP QD laser diodes with various cavity lengths by (MOVPE) technique.•Studying of L-I characteristics at various temperatures (190–390 K) for InP/AlGaInP QD laser diodes with various cavity lengths.•The threshold current density decreases with increasing cavity length in InP/AlGaInP QD laser diodes.•The characteristic temperature of threshold current decreases significantly with the cavity length.