Analysis of Field-Effect Passivation in Textured and Undiffused Silicon Surfaces

Türkay, Deniz; Köroğlu, Çağıl; Yerci, Selçuk

doi:10.1103/physrevapplied.12.034026

Cited by 5 publications

(2 citation statements)

References 78 publications

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“…[33][34][35] And this surface field effect has been modeled to explain the low recombination rate of surface photocarriers, highlighting the importance of the surface electric field on photocarrier extraction. [36,37] We comparatively illustrate the mechanisms playing in two types of devices-"far-field" and "near-field" in the Supporting Information (Figure S8, Supporting Information). It is the confluence of a variety of factors that results in the near-ideal quantum efficiency of the nanostalagmite b-Si device.…”

Section: Optoelectronic Characterizationmentioning

confidence: 99%

Facilely Achieved Self‐Biased Black Silicon Heterojunction Photodiode with Broadband Quantum Efficiency Approaching 100%

2022

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Photodiodes are fundamental components in modern optoelectronics. Heterojunction photodiodes, simply configured by two different contact materials, have been a hot research topic for many years. Currently reported self‐biased heterojunction photodiodes routinely have external quantum efficiency (EQE) significantly below 100% due to optical and electrical losses. Herein, an approach that virtually overcomes this 100% EQE challenge via low‐aspect‐ratio nanostructures and drift‐dominated photocarrier transport in a heterojunction photodiode is proposed. Broadband near‐ideal EQE is achieved in nanocrystal indium tin oxide/black silicon (nc‐ITO/b‐Si) Schottky photodiodes. The b‐Si comprises nanostalagmites which balance the antireflection effect and surface morphology. The built‐in electric field is explored to match the optical generation profile, realizing enhanced photocarrier transport over a broadband of photogeneration. The devices exhibit unprecedented EQE among the reported leading‐edge heterojunction photodiodes: average EQE surpasses ≈98% for wavelengths of 570–925 nm, while overall EQE is greater than ≈95% from 500 to 960 nm. Further, only elementary fabrication techniques are explored to achieve these excellent device properties. A heart rate sensor driven by nanowatt faint light is demonstrated, indicating the enormous potential of this near‐ideal b‐Si photodiode for low power consuming applications.

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Section: Optoelectronic Characterizationmentioning

confidence: 99%

Facilely Achieved Self‐Biased Black Silicon Heterojunction Photodiode with Broadband Quantum Efficiency Approaching 100%

2022

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“…However, it should be noted that it is unlikely that the corona charges can be deposited uniformly on a b-Si surface, which might, at least partly, explain this empirical result [14]. Using 2-D numerical simulations, Turkay et al [15] found that the surface nanofeatures would affect the field-effect passivation and that there could be a field-effect passivation enhancement for lightly doped c-Si under low-injection condition when Q f magnitude is moderate (5 × 10 8 cm −2 < |Q f | < 3 × 10 11 cm −2 for accumulation conditions and 3 × 10 10 cm −2 < |Q f | < 3 × 10 11 cm −2 for inversion conditions). Although these studies have shed some light on the nature of surface passivation of nanofeatures, the detailed mechanism of field-effect passivation on b-Si and its dependence on the nanofeature morphology should be systematically investigated.…”

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confidence: 99%

Field-Effect Passivation of Undiffused Black Silicon Surfaces

Wang

et al. 2021

IEEE J. Photovoltaics

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Black silicon (b-Si) surfaces typically have a high density of extreme nanofeatures and a significantly large surface area. This makes high-quality surface passivation even more critical for devices such as solar cells with b-Si surfaces. It has been hypothesized that conformal dielectrics with a high fixed charge density (Q f ) are preferred as the nanoscale features of b-Si result in a significant enhancement of field-effect passivation. This article uses 1-D, 2-D, and 3-D numerical simulations to study surface passivation of b-Si, where we particularly focus on the charge carrier control by |Q f | up to 1 × 10 13 cm −2 under accumulation conditions. We will show that there is a significant space charge region compression in b-Si nanofeatures, which affects the charge carrier population control for moderate |Q f | up to ≈1 × 10 12 cm −2 . The average surface minority charge carrier density can be reduced by 70% in some cases, resulting in an equivalent reduction in area-normalized surface recombination losses if the effective surface recombination velocity (S eff ) is limited by minority carriers. This provides a possible solution for the empirical S eff ∝ 1/Q 4 f reported previously. We will also show that the situation is more complicated for surface passivation films where the ratio between the electron and hole capture cross section (σ n / σ p ) is higher than 10 for p-type surfaces. For commonly used surface passivation films with a |Q f | larger than ≈1 × 10 12 cm −2 , there is little space charge compression for b-Si. Consequently, S eff simply scales with the surface area, i.e., there is no enhanced reduction of surface recombination by field-effect passivation on b-Si.

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Sub-50 cm/s surface recombination velocity in InGaAsP/InP ridges

Andrade

Hooten

Kim

et al. 2021

Applied Physics Letters

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The III–V InP/InGaAsP/InGaAs material family is important for photonic devices due to its optical emission and absorption in the 1.55 and 1.3 μm telecommunication bands for optical interconnects. However, InGaAsP/InGaAs generally suffer from relatively high surface recombination velocity—compared to Si [Das et al., in 2020 47th IEEE Photovoltaic Specialists Conference (PVSC) (IEEE, Calgary, AB, 2020), pp. 1167–1170] and InP [Joyce et al., Nano Lett. 12, 5325–5330 (2012)], which reduces the efficiency and can increase the noise in nanophotonic devices. Here, we demonstrate an efficient method to passivate the surface using a combination of sulfur-saturated ammonium sulfide and atomic layer deposition. After annealing, the surface passivation led to a surface recombination velocity as low as 45 cm/s, corresponding to a >180× increase in the photoluminesence of a nanoscale light-emitting device with 200 nm width.

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Analysis of Field-Effect Passivation in Textured and Undiffused Silicon Surfaces

Cited by 5 publications

References 78 publications

Facilely Achieved Self‐Biased Black Silicon Heterojunction Photodiode with Broadband Quantum Efficiency Approaching 100%

Facilely Achieved Self‐Biased Black Silicon Heterojunction Photodiode with Broadband Quantum Efficiency Approaching 100%

Field-Effect Passivation of Undiffused Black Silicon Surfaces

Sub-50 cm/s surface recombination velocity in InGaAsP/InP ridges

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