Origin of the Electroluminescence from Annealed-ZnO/GaN Heterojunction Light-Emitting Diodes

Abstract

This paper addressed the effect of post-annealed treatment on the electroluminescence (EL) of an n-ZnO/p-GaN heterojunction light-emitting diode (LED). The bluish light emitted from the 450 °C-annealed LED became reddish as the LED annealed at a temperature of 800 °C under vacuum atmosphere. The origins of the light emission for these LEDs annealed at various temperatures were studied using measurements of electrical property, photoluminescence, and Auger electron spectroscopy (AES) depth profiles. A blue-violet emission located at 430 nm was associated with intrinsic transitions between the bandgap of n-ZnO and p-GaN, the green-yellow emission at 550 nm mainly originating from the deep-level transitions of native defects in the n-ZnO and p-GaN surfaces, and the red emission at 610 nm emerging from the Ga-O interlayer due to interdiffusion at the n-ZnO/p-GaN interface. The above-mentioned emissions also supported the EL spectra of LEDs annealed at 700 °C under air, nitrogen, and oxygen atmospheres, respectively.

Enhancement of the near-band-edge electroluminescence from the active ZnO layer in the ZnO/GaN-based light emitting diodes using AlN-ZnO/ZnO/AlN-ZnO double heterojunction structure

“…The near UV luminescence became the dominant emission with a broad green-yellow luminescence. As referred to the previous reports [23,29,[31][32][33], the native defect transitions in the n-ZnO and p-GaN layers, such as oxygen (V O ) and/or gallium (V Ga ) vacancies, could be responsible for the green-yellow emission, with a peak at around 520 nm. Moreover, it was noted that the peak of the near UV luminescence emerged from the DH-ZnO/p-GaN LED shifted to a shorter wavelength of 412 nm as compared to that of the n-ZnO/p-GaN heterojunction LED.…”

“…In the previous paper, Ho et al fabricated a n-ZnO/p-GaN-based LED that emitted broad near UV luminescence by optimizing the transparent electrode contact to the n-type ZnO [14]. The origin of the red, green-yellow, and blue-violet emission in the EL spectra from the n-ZnO/p-GaN-based LEDs annealed under various ambient to cause the interfacial diffusion, had also been discussed [22,23]. In addition, Zheng et al also fabricated an AlN-ZnO/ZnO/AlN-ZnO DH structure using the rf magnetron cosputtering technology.…”

Mg-doped and chemo-thermally treated ZnO nanoflowers for ethanol sensing

“…Today ZnO is being deployed for applications such as gas sensors, solar cells, photodetectors, and liquid crystal displays [19][20][21]. Sensing, which is the target application in this study, has been one of the areas wherein ZnO has been found to be impactful [22][23][24]. However especially ethanol sensing using ZnO based nanostructures remains largely unexplored.…”