Effect of polarization state on optical properties of blue-violet InGaN light-emitting diodes

Suppression of electron overflow and efficiency droop in N-polar GaN green light emitting diodes

“…Simulations of reversed polarization emitters indicate several advantages over conventional emitters for device parameters such as electron overflow, injection efficiency, and laser threshold current density. 17,18 However, there have been very few experimental reports on InGaN/GaN quantum well emitters with reverse polarization due to the inherent challenges in growth and fabrication. [19][20][21] Ga-polar p-down devices have been investigated but found to be impractical due to the difficulty in obtaining low contact resistance to the etched p-type region and current crowding in resistive p-type epitaxial layers.…”

Effects of lateral current injection in GaN multi-quantum well light-emitting diodes

“…The material parameters used in the simulations are summarized in Table I, and the equations are solved using the finite element method (FEM) with a damped Newton iteration scheme. The effective masses (m à e , m à h ) and effective densities of states (N c , N v ) shown in Table I but not explicitely [18][19][20]. This choice is usually made to get a better agreement between simulations and experiment, and due to experimental evidence of significantly smaller polarization-induced surface charges than predicted theoretically.…”

“…21,22 Based on this, many computational studies of III-Nitride LEDs, including this, use polarization values that are about 50% of the theoretical estimates. [18][19][20] Even though we have mainly concentrated on the current spreading in this paper, the results are strongly related to the efficiency droop phenomenon observed in III-Nitride LEDs, because the uniform carrier distribution throughout the MQW structure reduces the droop. Furthermore, our simulations that account for nonradiative SRH and Auger recombination as well as current transport, suggest that increased Auger recombination is the principal reason for the droop.…”

Growth of N-polar GaN on vicinal sapphire substrate by metal organic chemical vapor deposition

“…It was also reported that polarization induced hole doping in compositionally graded AlGaN grown on GaN along the N-polarity direction, which can enhance the p-type doping efficiency and thus leads to great application in light emitting devices, particularly at deep ultraviolet region [8]. In addition, both theoretical and experimental studies show that N-polarization emitters show several advantages over conventional emitters for device parameters such as electron overflow, injection efficiency, and laser threshold current density [9][10][11].…”