Influence of well position on the electroluminescence characteristics of InGaN/GaN single quantum well red light-emitting diodes

In this paper, the influence of the position of InGaN layer well on the electroluminescence (EL) properties of red InGaN/GaN single quantum well (SQW) light-emitting diodes (LEDs) is investigated numerically. It is found that as the InGaN well shifts from the P-region to the N-region, the LED's EL intensity decreases, and the spectrum red-shifts. By analyzing the EL spectra, energy band structures and carrier distribution, it is considered that, when the well position moves away from the P-region, the injection barrier width of holes increases, while that of electrons decreases. Thus, the injection efficiency of electrons and holes is enhanced and weakened, respectively. Compared with electrons, the injection efficiency of holes with larger effective mass can be significantly reduced by a thicker barrier. As a result, the hole concentration in InGaN QW is reduced more severely, leading to a reduction in the total amount of carriers. The decreased concentration of injected carriers may weaken the carrier screening effect to the polarization electrical field, thereby the polarization-induced quantum confined-Stark effect is enhanced. As a consequence, for the SQW red LED whose InGaN well is far away from the P-region, the EL intensity of the SQW red LED is reduced and the peak wavelength becomes longer. • Electroluminescence (EL) properties of red InGaN/GaN single quantum well are studied. • As InGaN well shifts away from p-region, the EL intensity decreases and spectrum red-shifts. • The width of injection barrier for holes increases, while it decreases for electrons. • The hole concentration is reduced severely due to the larger effective mass. • The polarization effect is enhanced by the reduction in the total amount of carriers.