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We present our study on AlInN-based ultraviolet (UV) core-shell nanowire light-emitting diodes (LEDs) utilizing a polarization-induced doping technique. Due to the formation of a core-shell structure, the non-radiative recombination on the nanowire surface is significantly reduced. Moreover, we have successfully fabricated AlInN/GaN-based core-shell nanowire UV LED employing polarization-engineered quantum barriers instead of conventional structures. The LED device exhibits significantly improved carrier concentration in the active region and decreased electron leakage due to the gradually raised effective conduction band barrier heights. At room temperature, the AlInN LEDs exhibit strong and stable emission at 296 nm. We provide a promising approach to fabricating high-performance light emitters. 

From the past research results, it is evident that high-energy blue emission requires higher applied voltage in a blue nanowire light-emitting diode (LED) due to which difficulties such as self-heating and poor efficiency are developed. While designing a nanowire LED with III-nitride materials, the radiative recombination rate is reduced as the internal field of polarization inside the existing Ga-polar LEDs will tilt the energy band. But with the involvement of N-polar characteristics, the polarization field direction is reversed which eventually brings higher efficiency and lower turn-on voltage across the wavelength range. The subject of this work is to design and simulate an N-polar tunnel junction (TJ) blue nanowire LED to obtain better thermal as well as opto-electronic performances with minimal turn-on voltage. Moreover, TJ-LEDs show linear increases in light output powers (LOP) with varying current densities due to lower Auger recombination rates in their multi-quantum wells (MQWs). Within a temperature range of 30–150 , the proposed device obtains a lower thermal droop of 5.2 % at a current density of 40 A/cm2 which is 2.2 times less than the conventional one. 

Abstract In this work, an electron blocking layer (EBL) free light emitting diode (LED) nanowire is proposed with alternate prestrained layers of In_xGa_1−xN/GaN, which are inserted between the GaN/InGaN multi‐quantum wells (MQWs) and n‐GaN layer. This study signifies the role of prestrained layers on the piezoelectric polarization of LED nanowires, for enhanced luminescence. When compared with the conventional one, the EBL free LED nanowire with prestrained layer shows an enhancement of ~2.897% efficiency, which occurs due to the reduction of polarization field in the active region. The LED with 15% indium in the prestrained layer obtains a maximum efficiency of 85.21% along with a minimum efficiency droop of 3.848% at 40 mA injected current. The proposed III‐nitride LED nanostructure allows for achieving superior optical power across the output spectral range. 

In this paper, in order to address the problem of electron leakage in AlGaN ultra-violet light-emitting diodes, we have proposed an electron-blocking free layer AlGaN ultra-violet (UV) light-emitting diode (LED) using polarization-engineered heart-shaped AlGaN quantum barriers (QB) instead of conventional barriers. This novel structure has decreased the downward band bending at the interconnection between the consecutive quantum barriers and also flattened the electrostatic field. The parameters used during simulation are extracted from the referred experimental data of conventional UV LED. Using the Silvaco Atlas TCAD tool; version 8.18.1.R, we have compared and optimized the optical as well as electrical characteristics of three varying LED structures. Enhancements in electroluminescence at 275 nm (52.7%), optical output power (50.4%), and efficiency (61.3%) are recorded for an EBL-free AlGaN UV LED with heart-shaped Al composition in the barriers. These improvements are attributed to the minimized non-radiative recombination on the surfaces, due to the progressively increasing effective conduction band barrier height, which subsequently enhances the carrier confinement. Hence, the proposed EBL-free AlGaN LED is the potential solution to enhance optical power and produce highly efficient UV emitters. 

Abstract In this paper, a light-emitting diode in the ultra-violet range (UV-LED) with multiple-quantum wells (MQWs) of InGaN/GaN is designed and analyzed through Technology Computer-Aided Design (TCAD) simulations. The polarization effects in III-nitride heterojunction and the effects of graded composition in the electron blocking layer (EBL) are exploited to enhance the performance of the proposed UV-LED. It is observed that the effect of graded composition in the EBL helps to enhance the electrical and optical performance of the LED, thereby enabling the achievement of some promising results. The simulation-based results demonstrated that superior internal efficiency and an inferior leakage current are achieved by using a graded Al composition in the EBL rather than a uniform composition. The reported results also confirm the remarkable improvement of the light output power by 17% at ∼100 mA when using the graded composition and also show a reduction in series resistance leading to more current. Graded Al composition in the EBL results in the enhancement of electroluminescence spectra (i.e., an increase in the peak of the spectral density). 

We have demonstrated full-color and white-color micro light-emitting diodes (μLEDs) using InGaN/AlGaN core-shell nanowire heterostructures, grown on silicon substrate by molecular beam epitaxy. InGaN/AlGaN core-shell nanowire μLED arrays were fabricated with their wavelengths tunable from blue to red by controlling the indium composition in the device active regions. Moreover, our fabricated phosphor-free white-color μLEDs demonstrate strong and highly stable white-light emission with high color rendering index of ~ 94. The μLEDs are in circular shapes with the diameter varying from 30 to 100 μm. Such high-performance μLEDs are perfectly suitable for the next generation of high-resolution micro-display applications.