Browsing by Author "Hsu, Chung-Cheng"

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3D Finite Element Strain Analysis of V-Shaped Pits in Light Emitting Diodes
(2015)
Hsu, Chung-Cheng
;
Wu, Chen-Kuo
;
Li, Chi-Kang
;
Lu, Tien-Chang
;
Wu, Yuh-Renn
In this paper, we have analyzed the strain distribution of the V-pits in light emitting diodes (LEDs). The special geometry and non-uniform distribution introduce the complicated strain and piezoelectric distribution, where it might affect the carrier injection. In the future, we will combine the calculated piezoelectric field with our in-house developed 3D drift-diffusion model to figure out how the carrier inject into LEDs with V-pits.
3D numerical modeling of the carrier transport and radiative efficiency for InGaN/GaN light emitting diodes with V-shaped pits
(2016-05-01)
Li, Chi-Kang
;
Wu, Chen-Kuo
;
Hsu, Chung-Cheng
;
Lu, Li-Shuo
;
Li, Heng
In this paper, influence of a V-pit embedded inside the multiple quantum wells (MQWs) LED was studied. A fully three-dimensional stress-strain solver and Poisson-drift-diffusion solver are employed to study the current path, where the quantum efficiency and turn-on voltage will be discussed. Our results show that the hole current is not only from top into lateral quantum wells (QWs) but flowing through shallow sidewall QWs and then injecting into the deeper lateral QWs in V-pit structures, where the V-pit geometry provides more percolation length for holes to make the distribution uniform along lateral MQWs. The IQE behavior with different V-pit sizes, threading dislocation densities, and current densities were analyzed. Substantially, the variation of the quantum efficiency for different V-pit sizes is due to the trap-assisted nonradiative recombination, effective QW ratio, and ability of hole injections. (C) 2016 Author(s).