Abstract: The characteristic temperature calculations and dependency on quantum efficiency was analyzed for Pb_0.934 Sr_0.066 Se multiple quantum well structure at three temperature ranges; 77 K≤T₀≤150 K, 150≤T₀≤300 K and 77 K≤T₀≤300 K. Inclusion of theoretical values for the quantum efficiency due to auger recombination and leakage current reduces the characteristic Temperature (T₀) in these ranges. We compared the effects of including the theoretical quantum efficiency and an experimentally determined ones on the characteristic temperature values at a fixed cavity length of 600 μm. When results were compared to experimental data, it was concluded that there is a leakage current above the barrier due to thermionic emissionin the high temperature range 150≤T₀≤300 K. We estimated these additional values to be 246, 1353 and 5423 A cm^–2 at 200, 250 and 300 K, respectively. These are high values and hence, more work is needed to understand the thermionic emission process to improve on the performance of this material system and similar ones.