Current Blocking Layer Research Articles

Nitrogen-doped Ga2O3 current blocking layer using MOCVD homoepitaxy for high-voltage and low-leakage Ga2O3 vertical device fabrication

In this Letter, a high-quality and high-resistivity nitrogen (N)-doped Ga2O3 current blocking layer (CBL) is grown utilizing metal-organic chemical vapor deposition homoepitaxial technology. By using nitrous oxide (N2O) as oxygen source for Ga2O3 growth and N source for doping and controlling the growth temperature, the grown CBL can effectively achieve high (∼1019 cm−3) or low (∼1017 cm−3) N doping concentrations, as well as high crystal quality. Furthermore, the electrical properties of the developed CBL are verified at the device level, which shows that the device using the CBL can withstand bidirectional voltages exceeding 3.5 kV with very low leakage (≤1 × 10−4 A/cm2). This work can pave the way for the realization of high-voltage and low-leakage Ga2O3 vertical devices, especially metal-oxide-semiconductor field effect transistors.

High-Performance, High-Resolution Quantum Dot Light-Emitting Diodes with Self-Assembly Single-Molecular Interface Modification.

With the development of near-eye displays, the demands for display resolution and performance are increasing. Quantum dot performance is virtually independent of pixel size, making it an efficient way to display ultrahigh resolution. However, the low efficiency of high-resolution quantum dot devices has been an urgent technical bottleneck to be solved. Here, we constructed a dense single-molecule modification layer and a leakage current blocking layer for high-resolution devices using self-assembly, thereby realizing ultrahigh-resolution, high-efficiency, and stable high-resolution quantum dot light-emitting diodes (QLEDs). The peak external quantum efficiencies of the red devices are 24.68% (8759 PPI) and 19.54% (26075 PPI), respectively, with an exceptional long lifetime (T95@1000 nit) up to 4871 h. In addition, we explored the feasibility of this modification strategy on non-Cd-based quantum dots. In conclusion, our strategy effectively improves the performance of high-resolution devices and provides a superior approach for realizing near-eye display applications.

Numerical analysis on the performance enhancement in AlGaN/GaN vertical CAVET with InGaN/AlN/InGaN hybrid current blocking layer

Abstract In this paper, we propose an enhanced superjunction AlGaN/GaN vertical current aperture vertical electron transistor (CAVET) that integrates a novel hybrid InGaN/AlN/InGaN current blocking layer (CBL) situated above the P-column, directly beneath the channel. The incorporation of InGaN substantially elevates the device’s saturation output current by introducing a subchannel beneath the AlGaN/GaN heterojunction conducting channel. Nonetheless, the introduction of AlN engenders a two-dimensional hole gas of opposite polarization direction via the GaN/AlN heterojunction, which aids in depleting the two-dimensional electron gas within the channel, thereby mitigating the issue of negative threshold voltage (V th) bias occasioned by the subchannel introduced by InGaN. The outcomes demonstrate that the maximum saturation output current (I d) for the proposed architecture is 361.5 mA mm−1, with a V th of 1.63 V, marking increases of 98.6% and 0.08% over the traditional superjunction CAVET, respectively. Simultaneously, the breakdown voltage (V br) of the designed device is recorded at 12 064 V, and the specific on-resistance (R on,sp) is 6.45 Ω·mm, showcasing a enhancement figure of merit of 32.9% in comparison to the traditional superjunction CAVET.

High-performance β-Ga2O3 Schottky barrier diodes with Mg current blocking layer using spin-on-glass technique

This study presents a β-Ga2O3 Schottky barrier diode (SBD) with a Mg current blocking layer (Mg-CBL) fabricated via the Mg-doped spin-on-glass (Mg-SOG) technique, affording a surface roughness damage-free thermal doping process. The proposed technique improves the breakdown voltage (BV) of the β-Ga2O3 SBD from 580 to 2200 V and marginally increases the specific on-resistance from 4.0 to 4.8 mΩ cm2, yielding a notable power figure of merit exceeding 1 GW/cm2. The Mg-CBL effectively captures the electrons and mitigates the electric field, leading to a significant increase in BV and slight decrease in the forward current loss. The temperature-dependent I–V curves reveal that the reverse saturation current decreases owing to the physical mechanism of the Mg-CBL structure. Moreover, the Gaussian distribution model is applied to correct the Schottky barrier inhomogeneity stemming from the Mg-CBL. The results illustrate the promising potential of the Mg-CBL fabricated via the Mg-SOG technique for yielding high-performance β-Ga2O3 SBDs.

(Invited) Breakdown Improvement of Mg-Diffused Current Blocking Layer in Ga2O3

The path towards an all-planar highly efficient vertical Ga2O3 transistor requires the construction of a buried gate barrier junction to circumvent the pre-mature breakdown near the gate often seen in lateral structures. An effective selective doping technique is necessary to achieve this. By taking advantage of the high diffusivity of dopants and defects in Ga2O3, we propose the use of diffusion doping as a rapid and non-invasive technique to explore the possibility of an effective current blocking layer (CBL) in vertical Ga2O3 transistors. Unlike ion implantation, diffusion doping does not require an 1100°C annealing for the repair of crystal damage. Thus, the desired Mg doping profile can be maintained by the end of device fabrication, which is the key to achieving a high blocking voltage with Mg-doped CBL. In addition, diffusion doping can easily form a much deeper dope junction and be very useful for high-voltage and super-junction devices.Recently, we have demonstrated the first Ga2O3 vertical-diffused-barrier field-effect transistor (or VDBFET) utilizing a Mg-diffusion doped CBL with a spin-on-glass source. The transistor exhibited excellent FET behavior with decent saturation, enhancement-mode operation, and an on/off ratio of more than 109. However, the breakdown voltage is measured to be only 72V most likely due to the punch-through of the Mg-diffused CBL. This is likely caused by a lower-than-expected Mg doping rendering an inefficient electron blocking. In addition, SIMS analysis indicated the existence of Mg-H complex that deactivated the Mg. Thus, the effective Mg doping is even lower than its chemical concentration. Here we will discuss a new strategy to resolve this problem and showcase the characteristics of the improved CBL with a higher breakdown. This development paves the way for the development of high-voltage Ga2O3 VDBFETs.

Schottky-contact intrinsic current blocking layer for high efficiency AlGaInP-based red mini-LEDs.

AlGaInP-based red light emitting diodes (LEDs) are considered as promising light sources in future full-color displays. At present, vertical chip configuration is still the mainstream device structure of AlGaInP-based red LEDs. However, current crowding around p-electrode severely hinders an efficient improvement. Here, we propose a Schottky-contact current blocking layer (SCBL) to enhance current spreading and to improve light extraction efficiency of AlGaInP-based red vertical miniaturized LEDs (mini-LEDs). By utilizing the Schottky contact between ITO and p-GaP, the SCBL can hinder current crowding around the p-electrode. The current is forced to inject into an active region through a p-GaP+ ohmic contact layer, avoiding light absorption by p-electrode. Through the transfer length method, the Schottky contact characteristics between the ITO and p-GaP as well as the ohmic contact characteristics between ITO and p-GaP+ are demonstrated. Benefiting from superior current spreading and improved light extraction, a mini-LED with SCBL realizes an enhancement of 31.8% in external quantum efficiency (EQE) at 20 mA in comparison with a mini-LED without SCBL.

The optimization of a GaN-based current aperture vertical electron transistor

The main objective of this paper is to simulate and optimize a current aperture vertical electron transistor (CAVET) based on gallium nitride (GaN), which combines both a two-dimensional electron gas (2DEG) and a vertical structure using the SILVACO-TCAD simulator. The dimensions of the structure were reduced by 45% to minimize the size and improve the performances of the proposed device; also, a part of aluminum nitride (AlN)was added to the current blocking layer (CBL) to modulate the conduction band profile. The results obtained from the simulation of our structure demonstrated a maximum drain current of 1.8 A/mm, Pinch-off voltage (VP) of -6 V, drain induced barrier lowering (DIBL) of 166 mV/V, maximum transconductance (gm) of 570 mS/mm, gate-leakage of 7.10-7 A, cut-off frequency (ft) of 200 GHz, maximum oscillation frequency (fMax) of 400 GHz. The proposed device exhibited outstanding performance while consuming low power, making it well-suited for use as a low-noise amplifier (LNA) in satellite reception applications.

Slotted surface gratings fabricated by selective area growth of the p-InP cladding layer for BH lasers.

In this paper, we present a novel, to our knowledge, method for the fabrication of slotted surface gratings for buried heterostructure (BH) lasers. In the device fabrication process, SiO2 strips needed for InP current blocking layer growth are reused for the formation of slot grating pattern masks. In the following growth of the p-InP cladding layer, because the slot areas are covered by SiO2, the InP material is grown selectively in only the areas outside the slot areas, forming slots of the surface gratings in the p-InP layer at the same time as the cladding layer growth. Single longitude mode BH lasers having slotted surface gratings have been fabricated successfully, and the spectra show higher than 40 dB side mode suppression ratio (SMSR). The adoption of the method helps to simply the device fabrication and thus lower the device fabrication cost notably.

Design and simulation of high performance β-Ga2O3 super barrier rectifier with a current blocking layer

In this work, a β-Ga2O3 super barrier rectifier with a current blocking layer (CSBR) is proposed. Its static characteristics, dynamic characteristics and surge capability are investigated by TCAD simulation. The Baliga’s figure of merit (BFOM) can reach 1.62 GW cm−2 with the on-resistance of 3.68 mΩ cm−2 and the breakdown voltage of 2447 V, exhibiting excellent performance. Foremost, the turn-on and turn-off of the device is controlled by metal-oxide-semiconductor (MOS) structure. The reverse recovery time is 11.2 ns, which is compatible with that of a Schottky diode. Simulation results show that the dimensions of the cells and the proportion of the ohmic contact region in the cells are the key parameters affecting the reverse recovery time. In addition, the CSBR with double-side cooling configuration demonstrates high surge capability. It can sustain a peak surge current density of 5000 A cm−2, which is more than 10 times its forward current (V Forward = 3.0 V). Overall, the proposed structure has a high BFOM, excellent reverse characteristics and high reliability, demonstrating its potential in high voltage applications. Moreover, CSBR can be embedded into Ga2O3-MOSFET as a free-wheeling diode.

Electrical characteristics of in situ Mg-doped β-Ga2O3 current-blocking layer for vertical devices

The lack of p-type doping has impeded the development of vertical gallium oxide (Ga2O3) devices. Current blocking layers (CBLs) using implanted deep acceptors have been used to demonstrate vertical devices. This paper presents a pioneering demonstration of in situ Mg-doped β-Ga2O3 CBLs grown using metal–organic chemical vapor deposition. The Mg-doping density during growth was calibrated by quantitative secondary ion mass spectroscopy. Electrical test structures were designed with in situ Mg doped layers with various targeted Mg doping concentrations. The effectiveness of the CBL is characterized by using temperature-dependent current–voltage measurements using n-Mg-doped-n structures, providing crucial insight into the underlying mechanisms. Pulsed measurements show similar blocking characteristics as DC. To further validate the experimental results, a TCAD simulation is performed, and the electrically active effective doping is found to be dependent on the Mg-doping density, offering an alternate perspective on the optimization of CBL performance. Breakdown measurements show a peak 4 MV/cm field strength.

Phosphorous-doped graphene as an efficient interfacial layer material for application in solution-processed photodetectors

This work demonstrates solution-processed photodetectors (PDs) with perovskite as the active layer material, reduced graphene oxide as the hole transport layer and phosphorus-doped graphene (P-G) as the interfacial layer. High detectivity of over 1012 Jones was attained with PDs fabricated with the P-G layer, suggesting the great potential of the P-G layer as an additional dark current blocking layer. Analysis of the diode parameters indicated that this improved optoelectronic performance was attributed to decreased recombination, which resulted from a decrease in interface and trap defects and improved surface morphology, as evident from the field emission scanning electron microscope images. Recombination resistance, carrier lifetime and charge transport resistance were estimated using impedance spectroscopy analysis. It was observed that suppressed recombination due to improved surface morphology, including large grain size, is the main reason for the enhanced optoelectronic performance of PDs fabricated with the P-G layer. This work demonstrates that the use of an additional blocking/interfacial layer can be an effective strategy to improve the performance of solution-processed optoelectronic devices.

Design of the GaN based CAVET with SiO2–InGaN hybrid current blocking layer

The emergence of vertical GaN devices solves the problem of insufficient voltage withstand capacity of horizontal GaN devices. However, the current output capability of vertical GaN devices is not comparable to that of lateral GaN devices. So we propose a Al0.3Ga0.7N/GaN current-aperture vertical electron transistor with a SiO2–In0.05Ga0.95N hybrid current-blocking layer (CBL). Through simulation and in-depth study of the proposed device, the results show that the GaN/InGaN secondary channel enhances the saturation output current of the device, achieving a saturated output current (I DSS) of 985 mA mm−1 and a transconductance (G m) of 256 mS mm−1, which are 30% and 25% higher than that of the single-channel SiO2 CBL device, respectively. The breakdown voltage is 230 V and the on-resistance (R on) is only 0.58 mΩ cm2.

High-power diode lasers with in-situ-structured lateral current blocking for improved threshold, efficiency and brightness

We present high-power GaAs-based broad-area diode lasers with a novel variant of the enhanced self-aligned lateral structure ‘eSAS’, having a strongly reduced lasing threshold and improved peak conversion efficiency and beam quality in comparison to their standard gain-guided counterparts. To realize this new variant (eSAS-V2), a two-step epitaxial growth process involving in situ etching is used to integrate current-blocking layers, optimized for tunnel current suppression, within the p-Al0.8GaAs cladding layer of an extreme-triple-asymmetric epitaxial structure with a thin p-side waveguide. The blocking layers are thus in close proximity to the active zone, resulting in strong suppression of current spreading and lateral carrier accumulation. eSAS-V2 devices with 4 mm resonator length and varying stripe widths are characterized and compared to previous eSAS variant (eSAS-V1) as well as gain-guided reference devices, all having the same dimensions and epitaxial structure. Measurement results show that the new eSAS-V2 variant eliminates an estimated 89% of lateral current spreading, resulting in a strong threshold current reduction of 29% at 90 μm stripe width, while slope and series resistance are broadly unchanged. The novel eSAS-V2 devices also maintain high conversion efficiency up to high continuous-wave optical power, with an exemplary 90 μm device having 51.5% at 20 W. Near-field width is significantly narrowed in both eSAS variants, but eSAS-V2 exhibits a wider far-field angle, consistent with the presence of index guiding. Nonetheless, eSAS-V2 achieves higher beam quality and lateral brightness than gain-guided reference devices, but the index guiding in this realization prevents it from surpassing eSAS-V1. Overall, the different performance benefits of the eSAS approach are clearly demonstrated.

Performance improvement of AlGaInP based red LEDs by combination of omnidirectional mirror and AuZn micro-contacts

An omnidirectional reflector (ODR) consisted of (MgF2)/Ag was employed in AlGaInP-based vertical red light-emitting diodes (LEDs) in order to increase the light extraction hence the wall-plug efficiency. In this structure, the dielectric MgF2 layer with low refractive index acted as current blocking and reflection enhancing layer. The cylindrical AuZn alloy micro-contacts perforated through the MgF2 layer and played roles in current spreading and injection. The area ratio of AuZn micro-contacts was optimized to improve the performance of the LED. The results indicated that increasing the area ratio of micro-contacts led to the improvement of current injection uniformity and reduction of forward voltage especially at higher injection current, but at the expense of light extraction by reducing reflection. After optimized, the best performance of red-light LEDs can be obtained with 3% area ratio of micro-contacts.

Enhancement-mode β-Ga2O3 U-shaped gate trench vertical MOSFET realized by oxygen annealing

Vertical metal–oxide–semiconductor field effect transistor (MOSFET) is essential to the future application of ultrawide bandgap β-Ga2O3. In this work, we demonstrated an enhancement-mode β-Ga2O3 U-shaped gate trench vertical metal–oxide–semiconductor field effect transistor (UMOSFET) featuring a current blocking layer (CBL). The CBL was realized by high-temperature annealing under oxygen ambient, which provided electrical isolation between the source and drain electrodes. The CBL thicknesses of different annealing temperatures were derived from C–V measurements and the Fermi level position of the sample surfaces of different annealing temperature was characterized by x-ray photoelectron spectroscopy measurements, indicating good process controllability. Furthermore, photoluminescence spectra were measured to study the effect of oxygen annealing. The fabricated UMOSFET showed normally off with a Vth of 11.5 V, an on-state resistance of 1.48 Ω cm2, a maximum on-state current of 11 A/cm2, an on–off ratio of 6 × 104, and a three-terminal breakdown voltage over 100 V. This work paves a way to form a CBL and broadens the design space for high-power β-Ga2O3 vertical transistors.

Noise characterisation of GaN current aperture vertical electron transistor metal‐insulated semiconductor field effect transistor with Δ‐shaped gate for low noise radio frequency amplifiers

In this article, vertical CAVET with boron-doped GaN layer as current blocking layer (CBL) for AlGaN/GaN is proposed in this study, and different electrical characteristics of the devices, such as DC (Ids − Vds), small-signal radio frequency and high-frequency microwave noise performances, are characterised using Synopsys TCAD simulations. The vertical CAVET AlGaN/GaN metal-insulated semiconductor field effect transistor (MIS-HEMT) has been found to have a high threshold VT = 6.36 V, drain saturation current, Ids,sat = 3.41 kA/cm2, reduced OFF-state current <10−12 and improved high frequency and noise performances. The findings provide insight on noise sources and provide information on how to improve GaN transistor noise performance. Its useful characterisation tool for learning more about the imperfections in advanced AlGaN/GaN MIS-HEMTs and how they evolve. A two-port noise equivalent-circuit description is used to calculate data for noise. Using data from noise and scattering parameters that have been measured, we evaluated the effect of noise sources due to gate and drain, as well as their correlation. The devices exhibit a minimum noise figure (NFmin) and an equivalent noise resistance (Rn) of 1.21 dB and 20 Ω at 20 GHz, with Vgs = 5 V and Vds = 10 V, which is small and appropriate for low-noise amplifiers with a wide bandwidth. The maximum output power density Pout of 23 dBm and the maximum PAE of 63.3% are achieved for GaN V-shaped CAVET MIS-HEMTs with Vds = 10 V at 3.12 GHz is achieved. A comparison is made between the noise performance of conventional HEMTs, MIS-HEMTs and FETs. The methods for obtaining the noise figure (NFmin) and other noise metrics are then explained and compared with those found in the literature.

Study of GaN/InGaN Light-Emitting Diodes with Specific Zirconium Oxide (ZrO2) Layers

An interesting device design including a zirconium oxide (ZrO2) current blocking layer (CBL) and a ZrO2 surface passivation layer (SPL) is employed to manufacture a GaN/InGaN light-emitting diode (LED). Based on the inherently good performance of ZrO2, the current spreading effect and the undesired surface leakage are efficiently enhanced and suppressed, respectively. Energy-dispersive X-ray spectroscopy (EDS), atomic force microscopy (AFM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) are used to study the relevant properties. It is found that by series calibration, 50 nm is the proper thickness of the ZrO2 CBL and SPL. The peak emission wavelength of the proposed LEDs is around 452 nm. Experimentally, at the operating condition of 110 A cm−2, the proposed Device L3 with a 50 nm-thick ZrO2 CBL and a 50 nm-thick ZrO2 SPL demonstrates improvements of 66.1% in light output power (LOP) and 64.5% in wall plug efficiency (WPE) as compared to a traditional Device L1 without the specific design. Furthermore, the proposed Device L3 presents a notable enhancement in the light emission mapping image in comparison to the traditional LED. So, the proposed device design which incorporates a proper ZrO2 CBL and ZrO2 SPL, is beneficial for manufacturing GaN/InGaN LEDs.

A Novel GaN LED Structure With Both P and N Discontinuous Ohmic Contacts and Discontinuous CBL

In this paper, a novel kind of GaN light-emitting diode (LED) with P and N discontinuous ohmic contact electrodes and discontinuous current blocking layer (CBL) is designed and prepared. Multiple contact windows under the N- and P-electrodes formed by etching help realize the discontinuous ohmic contacts with the N-GaN layer and the ITO layer, respectively. Similarly, by etching a plurality of discontinuous openings with the same pitch in the CBL, a discontinuous CBL structure is formed. As compared with traditional structures, the discontinuous ohmic contacts can maximize the number of current paths which allow the carriers to be collected from all four directions, leading to a more uniform current spreading and thermal management. Furthermore, as the contacts are not continuous any longer, some of the otherwise removed materials (such as the active region) lying between the patches are saved. The optoelectronic characteristics, junction temperature, thermal resistance, and infrared thermography measurements are conducted and the current distribution is simulated. The results show that the novel LED structure has better optoelectronic performances and current spreading ability compared to traditional devices. At 150 mA current, the luminous efficiency is 15.2% higher than the traditional LED, the junction temperature is reduced by 4.9%, and the thermal resistance is reduced by 12%.

Enhancement-Mode Heterojunction Vertical β-Ga2O3 MOSFET with a P-Type Oxide Current-Blocking Layer

The vertical heterojunction Ga2O3 MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) with the p-type oxide as the current-blocking layer (CBL) is investigated for the first time using SILVACO simulation software. The results show that the threshold voltage of the device is easily positive, which means that the device works in the enhancement mode. By adjusting the doping concentration (from 2 × 1017 cm−3 to 2 × 1018 cm−3) and thickness (from 0.4 um to 2 um) of p-SnO CBL, the threshold voltage is around from 2.4 V to 2.8 V and the breakdown voltage of the device can be increased from 361 V to 518 V. Compared with the original homojunction Ga2O3 vertical MOSFET with CBL, the p-SnO CBL can greatly improve the performance of the device. Other p-type oxides are also investigated as the CBL and show promising performances. This work has a certain guiding significance for the design of a vertical enhanced current-blocking layer MOSFET device and for the development of a Ga2O3 heterojunction power device.

Study of a GaN-Based Light-Emitting Diode With a Ga₂O₃ Current Blocking Layer and a Ga₂O₃ Surface Passivation Layer

A new device structure, which includes a Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> current blocking layer (CBL) and a Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> surface passivation layer (SPL), is used to fabricate a GaN-based light-emitting diode (LED). Due to the inherent properties of Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> material, the current spreading phenomenon can be effectively improved and the surface leakage current and Fresnel reflection can be remarkably reduced. The appropriate thicknesses of the Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> CBL and SPL, according to the results from series experiments, are 10 and 50 nm, respectively. In an experiment, under an injection current density of 100 A/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , the studied LED device with a 10 nm-thick Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> CBL and a 50 nm-thick Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> SPL shows enhancements of 76.8%, 60.7%, 76.8%, and 56.2% in light output power (LOP), luminous efficacy, external quantum efficiency (EQE), and wall-plug efficiency, respectively, in comparison to a conventional LED without the designed structure. In addition, the studied LED exhibits obvious improvement in far-field radiation pattern compared to the conventional LED device. Thus, the studied structure, which includes an appropriate Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> CBL and SPL, offers a promising route to fabricate high-performance GaN-based LEDs.