Evaluation of radiative efficiency in InGaN blue-violet laser-diode structures using electroluminescence characteristics

Abstract

The authors analyzed radiative efficiency of InGaN laser diodes (LDs) emitting at 405nm. Based on semiconductor rate equations, the radiative efficiency is unambiguously determined by the analysis of electroluminescence characteristics. The radiative efficiency exceeds 70% even far below threshold of ∼3mA at a high temperature of 80°C. This highly radiative characteristic is attributed to reduced contribution of nonradiative recombination in LDs with low-dislocation-density active material. It is also found that the radiative efficiency is almost independent of threshold current, indicating that nonradiative recombination is not a major factor which determines lasing threshold in 405nm emitting InGaN LDs having low dislocation density.

Quality and thermal stability of thin InGaN films

“…Based on the equation for total recombination: R total =An+Bn 2 +Cn 3 , we get direct access to the ratio of radiative-to-non-radiative recombination for lower carrier densities n. The term An describes the non-radiative, Bn 2 the radiative recombination processes and Cn 3 the Auger losses. In a double-logarithmic plot of integrated EL intensity versus current density the non-radiative recombination shows a slope of two, the radiative recombination a slope of 1 and the Auger losses a slope of 2/3 [4].…”

Extremely high absolute internal quantum efficiency of photoluminescence in co-doped GaN:Zn,Si

“…High values of the absolute IQE of PL in GaN or InGaN were reported, in the range of 30%-70%. [3][4][5][6] However, assumptions for the method used in these publications to estimate the absolute IQE require better justification.…”

Carrier recombination mechanisms and efficiency droop in GaInN/GaN light-emitting diodes

“…We obtain the carrier concentration n by assuming a B value of 10 −10 cm 3 s −1 . 2,[10][11][12][13] Figure 3͑a͒ shows the IQE as a function of carrier concentration.…”