Improving the Efficiency of GaInP/GaAs Light Emitters Using Surface Passivation

Tripathi, T. S.; Radevici, Ivan; Dagytė, Vilgailė; Sadi, Toufik; Oksanen, Jani

doi:10.1109/ted.2020.3006801

Cited by 5 publications

(3 citation statements)

References 40 publications

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“…In a broader sense, this has positive implications for the hole-selective GaAs solar cell fabrication as it suggests that non-epitaxial GaAs passivation methods with materials without the requirement for the hole-selective band alignment are feasible for attaining high V OC . Non-epitaxial passivation methods include, for example, sulfur treatment ,, and atomic layer deposition . As such, both crystal growth and surface passivation can in the future be feasible without MOCVD, which will enable the use of a broad selection of growth and passivation techniques.…”

Section: Resultsmentioning

confidence: 99%

CuI as a Hole-Selective Contact for GaAs Solar Cells

Haggrén

Raj

Haggren

et al. 2022

ACS Appl. Mater. Interfaces

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Carrier-selective contacts have emerged as a promising architecture for solar cell fabrication. In this report, the first hole-selective III–V semiconductor solar cell is demonstrated using copper iodide (CuI) on i-GaAs. Surface passivation quality of GaAs is found to be essential for open-circuit voltage (V OC), with good correlation between photoluminescence properties of the GaAs layer and the V OC. Passivation with <10 nm thick In0.49Ga0.51P layers is shown to provide an over 300 mV improvement. Oxygen-rich CuI is formed by natural oxidation in the atmosphere, and the increased oxygen content of ∼10% is validated by energy-dispersive X-ray measurements. The oxygen incorporation is shown to improve hole selectivity and thus solar conversion efficiency. Ultraviolet photoelectron spectroscopy indicates a high work function of ∼6 eV for the oxygen-rich CuI. With optimized GaAs surface passivation and oxygen-rich CuI, a V OC of nearly 1 V and a solar conversion efficiency of 13.4% are achieved. The solar cell structure includes only undoped GaAs, a surface passivation layer, and non-epitaxial CuI contact and is therefore very promising to various low-cost crystal growth methods. The results have a significant impact on III–V solar cell fabrication and costs as it (i) enables fully carrier-selective architectures, (ii) reduces cell fabrication complexity, and (iii) is suitable for layers grown by low-cost crystal growth techniques.

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Section: Resultsmentioning

confidence: 99%

CuI as a Hole-Selective Contact for GaAs Solar Cells

Haggrén

Raj

Haggren

et al. 2022

ACS Appl. Mater. Interfaces

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“…Therefore, nonradiative surface recombination at the perimeter sidewall becomes one of the most important loss mechanisms limiting the IQE. ,, Over the past few decades, various strategies have been developed to combat perimeter recombination. Examples include chalcogenide-based wet-chemical passivation, − field-effect dielectric passivation, , wet-chemical or plasma nitridation, , and epitaxial regrowth . However, all of these methods require complex processing techniques or nonstandard equipment and suffer from poor longevity or incomplete passivation.…”

Section: Introductionmentioning

confidence: 99%

Reduced Surface Recombination in Extended-Perimeter LEDs toward Electroluminescent Cooling

van der Krabben,

Gruginskie,

van Eerden

et al. 2024

ACS Appl. Electron. Mater.

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III−V semiconductor light-emitting diodes (LEDs) are a promising candidate for demonstrating electroluminescent cooling. However, exceptionally high internal quantum efficiency designs are paramount to achieving this goal. A significant loss mechanism preventing unity internal quantum efficiency in GaAsbased devices is nonradiative surface recombination at the perimeter sidewall. To address this issue, an unconventional LED design is presented, in which the distance from the central current injection area to the device's perimeter is extended while maintaining a constant front contact grid size. This approach effectively moves the perimeter beyond the lateral spread of current at an operating current density of 10 1 −10 2 A/cm 2 . In p−i−n GaAs/InGaP double heterojunction LEDs fabricated with varying sizes and perimeter extensions, a 19% relative increase in external quantum efficiency is achieved by extending the perimeter-tocontact distance from 25 to 250 μm for a front contact grid size of 450 × 450 μm 2 . Utilizing an in-house developed Photon Dynamics model, the corresponding relative increase in internal quantum efficiency is estimated to be 5%. These results are ascribed to a significant reduction in perimeter recombination due to a lower perimeter-to-surface area (P/A) ratio. However, in contrast to lowering the P/A ratio by increasing the front contact grid size of LEDs, the present method enables these improvements without affecting the required maximum current density in the microscopic active LED area under the front contact grid. These findings aid in the advancement of electroluminescent cooling in LEDs and could prove useful in other dedicated semiconductor devices where perimeter recombination is limiting.

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“…Being a direct bandgap semiconductor, gallium arsenide (GaAs) possesses interesting optical properties to manipulate light-matter interactions in optoelectronic devices such as solar cells [14], nano-lasers [15], photodetectors [16], and light emitting diodes [17]. In this regard, extensive research has been conducted to enhance light absorption in ordered GaAs NW arrays.…”

Section: Introductionmentioning

confidence: 99%

Disorder induced absorption enhancement of light in GaAs nanowire array

Shahnewaz¹,

Iqbal²,

Baten³

et al. 2022

J. Opt.

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Light absorption characteristics of vertically aligned GaAs nanowire (NW) arrays with disordered diameters and heights are investigated in this work using finite diﬀerence time domain (FDTD) analysis technique. By varying the random height ranges, an optimum variation range of 1000-2000 nm is obtained that provides the maximum average absorbance at diﬀerent fill-factors of the arrays. An array having random heights of the nanowires within the optimized range is found to have better absorbance for both normal and oblique incidence of light compared to the uniform height structure. Even for 45 degree incidence angle of light, average absorbance is obtained to be 2% higher for the random-height array, compared to the case of absorbance obtained for the uniform height structure. The proposed arrays having random diameters provide up to 12.8 % improvement in short circuit current density whereas the random-height structure enhances the short circuit current density by 1.1 % compared to the arrays having uniform diameter and height. The present work also provides an eﬀective medium theory based theoretical model taking into account the random height variation of the arrays. The theoretically calculated values are found to be in good agreement with FDTD simulation results, thereby providing further guidelines for designing random array based high performance photonic devices.

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Improving the Efficiency of GaInP/GaAs Light Emitters Using Surface Passivation

Cited by 5 publications

References 40 publications

CuI as a Hole-Selective Contact for GaAs Solar Cells

CuI as a Hole-Selective Contact for GaAs Solar Cells

Reduced Surface Recombination in Extended-Perimeter LEDs toward Electroluminescent Cooling

Disorder induced absorption enhancement of light in GaAs nanowire array

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