Temperature dependence of the threshold current density in InP-Ga0.28In0.72As0.6P0.4 (λ=1.3 μm) double heterostructure lasers

Abstract

The experimental threshold current density Jth(T) in InP-Ga0.28In0.72As0.6P0.4(λ=1.3 μm) double heterostructure lasers varies with temperature as exp(T/T0) with T0≂100 K for 100 K <T<250 K and with T≂65 K for 250 K<T<350 K. Numerous mechanisms have been suggested to explain this observed temperature dependence. The temperature dependence of gain gives T0≂100 K for T between 100 and 250 K, and T0≂200 K for T between 250 and 350 K. Inclusion of the temperature dependence of the Auger recombination and carrier concentration at threshold reduces T0 to ∼100 K in the 250 to 350 K temperature range. A leakage current of one-third of the total current at 300 K is required to reduce T0 to 65 K for 250 K<T<350 K. This leakage current is due to the hot carriers that result from Auger recombination and some of these carriers do not lose sufficient energy by interactions with the lattice to be confined by the heterojunction barriers. Previous experimental measurements found that the leakage current was 10–30% of the total current at room temperature. Another suggested cause of the small T0 is intervalence-band absorption. Extension of results for intervalence-band absorption in InP to Ga0.28In0.72As0.6P0.4 demonstrates that intervalence-band absorption is not significant.