Increase in the Shockley–Read–Hall recombination rate in InGaN/GaN QWs as the main mechanism of the efficiency droop in LEDs at high injection levels
- 94 Downloads
It is shown that the efficiency droop observed as the current through a GaN-based light-emitting diode increases is due to a decrease in the Shockley–Read–Hall nonradiative lifetime. The lifetime decreases with increasing current because a steadily growing number of traps in the density-of-states tails of InGaN/GaN quantum wells become nonradiative recombination centers upon the approach of quasi-Fermi levels to the band edges. This follows from the correlation between the efficiency droop and the appearance of negative differential capacitance, observed in the study. The correlation appears due to slow trap recharging via the trap-assisted tunneling of electrons through the n-type barrier of the quantum well and to the inductive nature of the diode-current variation with forward bias.
KeywordsIdeality Factor Forward Bias External Quantum Efficiency Exponential Tail Injection Level
Unable to display preview. Download preview PDF.
- 12.Tunneling Phenomena in Solids, Ed. by E. Burstein and S. Lundqvist, Lectures presented at the 1967/NATO Advanced Study Institute at Risö, Denmark (Plenum, New York, 1969; Moscow, Mir, 1973).Google Scholar
- 21.R. F. Kazarinov, V. I. Stafeev, and R. A. Suris, Sov. Phys. Semicond. 1, 1084 1967.Google Scholar
- 22.A. Rose, Concept in Photoconductivity and Allied Problems (Krieger, New York, 1978).Google Scholar
- 24.A. G. Kazanskii and E. P. Milichevich, Sov. Phys. Semicond. 18, 1137 1984.Google Scholar