Stacking-enabled Si/GaN tunnel junction light-emitting diodes with improved radiative recombination efficiency

Abstract

Improving carrier injection for radiative recombination in GaN light-emitting diodes (LEDs) has been a major focus for several decades. In this study, the performance of GaN LEDs was enhanced through the construction of an Si/GaN tunnel junction (TJ) via nanomembrane (NM) stacking. The n + Si nanomembrane was transfer printed onto the p + GaN layer, resulting in an n + Si/p + GaN TJ on top of the GaN epi-structure. The radiative recombination of electron–hole pairs was enhanced by the tunneling of carriers across the Si/GaN TJ into the InGaN/GaN multi-quantum wells. The improved hole injection was elucidated through the energy band diagram of the Si/GaN TJ. The increased number of injected holes in the stacked Si/GaN TJ LED leads to enhanced radiative recombination, resulting in greater output power and external quantum efficiency (EQE). Specifically, the light output power improved by 96% at 30 A/cm², and the peak EQE increased by 36% due to the formation of the stacked Si/GaN TJ on the LED. These findings can be applied to the manufacturing of electronic devices, where balancing carrier generation and injection is crucial for operational efficiency.