Analysis of InGaN Multiple-Quantum-Well Photoelectric Device of Visible Light Communication

The key to achieving high-speed and high-quality visible light communication is to increase the modulation speed of Light-Emitting Diode (LED). Therefore, in this study, the influence of the Composite Mechanism of Carrier (CMC) on the modulation speed of LED is studied by designing different structures of the InGaN Multi-quantum-well (MQW) LED active region. Because the carrier subspace waves function of narrow quantum well LED overlaps more frequently and the electron leakage effect is more significant, the compound rate is faster and the modulation bandwidth is higher. InGaN quantum barrier LED with a content of 1% can increase the weight of radiation recombination, which makes the modulation bandwidth higher than GaN quantum barrier LEDs; when the in content is 5%, electron leakage and Auger recombination have a dominant position. Moreover, because these two compounding mechanisms have a fast compounding rate, the modulation bandwidth is significantly increased. Then the 405 nm laser-excited photoluminescence (PL) is introduced to analyze the carrier dynamics in the LED and obtain the related processes of carrier distribution and transport. The proposed carrier microscopic model can well explain change characteristics of the PL luminescence peak, luminous intensity, and half-height width of InGaN/GaN MQW LED with different excitation wavelengths. At low temperature, the PL peak of the InGaN/GaN quantum well LED redshifts with the increase of temperature, because the weakly bound carrier transfers the obtained energy to the deeply bound energy level of high In content.