Modelling charge transport and electro-optical characteristics of quantum dot light-emitting diodes

Abstract

AbstractsQuantum dot light-emitting diodes (QD-LEDs) are considered as competitive candidate for next-generation displays or lightings. Recent advances in the synthesis of core/shell quantum dots (QDs) and tailoring procedures for achieving their high quantum yield have facilitated the emergence of high-performance QD-LEDs. Meanwhile, the charge-carrier dynamics in QD-LED devices, which constitutes the remaining core research area for further improvement of QD-LEDs, is, however, poorly understood yet. Here, we propose a charge transport model in which the charge-carrier dynamics in QD-LEDs are comprehensively described by computer simulations. The charge-carrier injection is modelled by the carrier-capturing process, while the effect of electric fields at their interfaces is considered. The simulated electro-optical characteristics of QD-LEDs, such as the luminance, current density and external quantum efficiency (EQE) curves with varying voltages, show excellent agreement with experiments. Therefore, our computational method proposed here provides a useful means for designing and optimising high-performance QD-LED devices.

Numerical Model of Current Flow and Thermal Phenomena in Lateral GaN/InGaN LEDs

“…It implies that although the current parallel to the junction plane can be treated as drift only, the current perpendicular to this plane consists of both drift and diffusion components. It can be solved by introducing the diode equation into the model, as in the case of the resistor network model [23]. However, it is impossible in the case of the model using a numerical solution of the Poisson Equation (2).…”

“…W neutral conditions, one can layers except the MQW reg the current carriers, which allowed to determine the dr law described by Equation ( tric field strength E or the e erty. In the model, the nece merical solution of the Pois The MQW region requ n diode under forward bias that almost the entire area although the current paralle perpendicular to this plane solved by introducing the network model [23]. Howev solution of the Poisson Equa sisting in introducing an art ponents σ‖ and σ﬩ represe to the junction plane, respec ity of the region and allows one covers the superpositio characteristic calculated wi TAURUS package has been (see Figure 3a) extracted fr layers and their properties tails, see [25].…”

“…Since both the power LED operating conditions and its reliability are very sensitive to the current distribution, a lot of effort has been devoted both to its evaluation and to its optimisation at the stage of the device design. The conducted studies cover twodimensional approaches employing models limited to the current flow described by an appropriate resistance network or the Poisson Equation [19][20][21][22], as well as more complex models, based on the numerical solution of the physical drift-diffusion model of the semiconductor structure [17,[23][24][25]. The first approach deals with the drift current flow in a 2D or 3D domain covering all the diode design layers and their properties but simplify or even neglect some phenomena taking place in the modelled domain, especially in the junctions.…”

“…In addition, they require many physical parameters that are difficult to get, and very dense computational grids. They are very useful in the case of device-oriented simulations, where the insight in the design of the semiconductor device is necessary, e.g., to improve LED efficiency [24], to test new structure designs [15], or to introduce new quantum effects to the models [23].…”

Optoelectronic system and device integration for quantum-dot light-emitting diode white lighting with computational design framework

“…Next, the device-level simulation of QD-LEDs is carried out by a complete charge transport model with a detailed electric-field dependant carrier injection model 27 , 29 , 30 , 35 to predict the electro-optical properties including the intrinsic spectral radiances of the monochromatic QD-LED devices. The optoelectronic simulations are extended to design the layout of the multiple pixelated QD-LEDs.…”