Hole transport improvement in CdZnO/ZnO light emitting diodes with wedge shaped electron blocking layers

다국어 초록 (Multilingual Abstract)

Carrier transport characteristics of current injected II-VI CdxZn1−xO∕ZnO quantum well (QW) light emitting diodes (LEDs) were theoretically studied, by using both conventional square shaped and wedge-shaped electron blocking layers (EBLs).
CdZnO∕ZnO QW LEDs with wedge EBL layers exhibited a much improved hole injection rate compared to LEDs with square EBL layers. By the enhanced hole injection efciency, a balance in the injected electron and hole concentrations are promoted. Therefore, the radiative recombination rate is signifcantly enhanced in the LEDs with wedge-shaped EBL. In addition, we observed that the insertion of the wedge-shaped EBL signifcantly reduces the efciency droop which is the reduction of internal quantum efciency (IQE) with increasing injection current density. It is expected that the CdZnO∕ZnO QW LED with a wedge-shaped EBL is advantageous for the high power light emission via the minimization of efciency droop, especially in the high injection current range.