We report on the illustration of the first electron blocking layer (EBL) free AlInN nanowire light-emitting diodes (LEDs) operating in the deep ultraviolet (DUV) wavelength region (sub-250 nm). We have systematically analyzed the results using APSYS software and compared with simulated AlGaN nanowire DUV LEDs. From the simulation results, significant efficiency droop was observed in AlGaN based devices, attributed to the significant electron leakage. However, compared to AlGaN nanowire DUV LEDs at similar emission wavelength, the proposed single quantum well (SQW) AlInN based light-emitters offer higher internal quantum efficiency without droop up to current density of 1500 A/cm2and high output optical power. Moreover, we find that transverse magnetic polarized emission is ∼ 5 orders stronger than transverse electric polarized emission at 238 nm wavelength. Further research shows that the performance of the AlInN DUV nanowire LEDs decreases with multiple QWs in the active region due to the presence of the non-uniform carrier distribution in the active region. This study provides important insights on the design of new type of high performance AlInN nanowire DUV LEDs, by replacing currently used AlGaN semiconductors.
AlGaN nanowires with inverse taper for flexible DUV emitters
Deep ultraviolet (DUV) AlGaN light-emitting diodes (LEDs) are promising alternatives for production of DUV light, offering many advantages over mercury arc lamps. In this work, AlGaN nanowires with an inverse taper profile were demonstrated through a wet etching process, enabling removal of the nanowires from the growth substrate in a novel peeling process to form flexible devices. AlGaN nanowires with taper angles of ∼22° were obtained following a 70 min etch in AZ400K. Nanowire taper angle was studied as a function of etch time and nanowire top diameter. Nanowires with inverse taper were then embedded in a flexible polymer layer and removed from their growth substrate, which could enable development of high-efficiency flexible micro-LEDs. Released nanowires embedded within the polymer liftoff layer exhibit strain relaxation induced redshift due to reduction in piezoelectric polarization electric field intensity. The inverse taper structure was found to promote enhanced light extraction from the nanowire. The demonstrated flexible DUV emitters with inverse taper are shown to improve the device efficiency and allow for realization of flexible emitters through a novel fabrication process for the first time.
more » « less- Award ID(s):
- 1751675
- NSF-PAR ID:
- 10361790
- Publisher / Repository:
- IOP Publishing
- Date Published:
- Journal Name:
- Journal of Physics: Photonics
- Volume:
- 3
- Issue:
- 2
- ISSN:
- 2515-7647
- Page Range / eLocation ID:
- Article No. 024016
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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