Electrostatic Tuning of Ionic Charge in SiO<sub>2</sub> Dielectric Thin Films

Al‐Dhahir, Isabel; Kealy, Rachel; Kelly, Samira; Yu, Mingzhe; McNab, Shona; Collett, Katherine A.; Liu, Junliang; Grovenor, C.R.M.; Wilshaw, Peter R.

doi:10.1149/2162-8777/ac7350

Cited by 3 publications

(4 citation statements)

References 72 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The kinetics of alkali ion migration have been studied in detail in ref. [20], including the processes involved in the ionic migration and how concentrations can be tailored by adjusting the annealing and charging parameters. On a subset of specimens, a PECVD silicon nitride (SiN x ) thin film was deposited using a PlasmaPro 80 reactor from Oxford Instruments, and using a non-optimized recipe including a 20:2:29 ratio of silane, ammonia, and nitrogen, and deposited at 350 °C.…”

Section: Methodsmentioning

confidence: 99%

“…In this work it has been assumed that the charge is fully concentrated at the Si-SiO 2 interface, such that, x c = d, following findings in refs. [7,20].…”

Section: Methodsmentioning

confidence: 99%

“…This temperature is different than that chosen for K + ions since the migration kinetics are slower as we have recently reported. [ 20 ] We chose the temperatures based on a migration process that can be conducted in a less than 5 min. As before, the interface charge was controlled by varying the concentration of corona charge deposited prior to the anneal.…”

Section: Field Effect Passivation From Alkali Ion Charged Sio2mentioning

confidence: 99%

“…Our recent work identified the key kinetic mechanisms for K + , Rb + , and Cs + ion migration into thin oxide films. [ 20 ] Here we expand such work to look at the potential of ICDs as efficient and stable surface passivation nanolayers.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Ion‐Charged Dielectric Nanolayers for Enhanced Surface Passivation in High Efficiency Photovoltaic Devices

Al‐Dhahir

Niu

et al. 2023

Adv Materials Inter

Self Cite

View full text Add to dashboard Cite

limitation in achieving high efficiency is the recombination of electrons and holes at the silicon surface. For high efficiency PERC and TOPCon structures to exploit their full performance, superb passivation techniques are required at surfaces and interfaces in the cell. [1] A common method to reduce surface recombination is to deposit a dielectric thin film, typically a double layer of SiO 2 /SiN x , upon the silicon surface. This serves to chemically passivate the surface, while the dielectric's intrinsic charge provides an electric field that modulates charge carrier population and further reduces recombination. [2] The latter effect is commonly termed field effect or charge assisted passivation and can be exploited in a variety of solar cell technologies. [3,4] The effectiveness of such dielectrics can be further improved by extrinsic methods that modify the film properties after deposition. This work explores how field effect surface passivation in thin film dielectrics can be enhanced by adding extrinsic ionic charge. We term this kind of charged thin film an "ion-charged dielectric."In ion-charged dielectrics (ICDs), cations or anions are purposely embedded inside of the dielectric with the purpose of producing a large and permanent electric field. Such charge can add functionality and improve the performance of electronic devices, especially the surface passivation of silicon solar cells. [5] To date, the electric field in ICDs has been primarily demonstrated using embedded potassium and sodium cations, [6][7][8][9] with some work also using cesium ions. [10,11] While the field effect provided by such ions has shown promising results, it is possible that alternative positive and negative ions can provide greater control and stability. Methods of incorporating ions into dielectrics include ion implantation, [12] in situ delivery during oxidation, [6,8] or wet delivery prior to chemical vapor deposition. [10,11] Recently, a novel method of introducing ions to dielectrics extrinsically, after deposition, was proposed by the authors. [13,14] In this method an aqueous precursor containing KCl is thermally evaporated onto the SiO 2 surface followed by elevated temperature annealing to drive the ions to the Si-SiO 2 interface. Relying on pure diffusion kinetics, it was found that the transport time of K + ions across SiO 2 varied from several minutes at 500 °C to over an hour at 400 °C. Later work evaluated the transport time of K + ions in the presence of a surface electric field generated by a corona discharge. [7] It was foundThe power conversion efficiency of solar cells is strongly impacted by an unwanted loss of charge carriers occurring at semiconductor surfaces and interfaces. Here the use of ion-charged oxide nanolayers to enhance the passivation of silicon surfaces via the field effect mechanism is reported. The first report of enhanced passivation from rubidium and cesium ion-charged oxide nanolayers is provided. The charge state and formation energy of ioncharged silicon dioxide are calculated from ...

show abstract

Section: Methodsmentioning

confidence: 99%

“…In this work it has been assumed that the charge is fully concentrated at the Si-SiO 2 interface, such that, x c = d, following findings in refs. [7,20].…”

Section: Methodsmentioning

confidence: 99%

Section: Field Effect Passivation From Alkali Ion Charged Sio2mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Ion‐Charged Dielectric Nanolayers for Enhanced Surface Passivation in High Efficiency Photovoltaic Devices

Al‐Dhahir

Niu

et al. 2023

Adv Materials Inter

Self Cite

View full text Add to dashboard Cite

show abstract

Hole-Selective SiN_x and AlO_x Tunnel Nanolayers for Improved Polysilicon Passivating Contacts

McNab,

Morisset,

Libraro

et al. 2024

ACS Appl. Energy Mater.

View full text Add to dashboard Cite

A highly efficient hole-selective passivating contact remains the crucial step required to increase the efficiency of polysilicon-based Si solar cells. The future development of solar modules depends on a device structure that can complement the electron-selective tunnel oxide passivating contact with an equivalent hole-selective contact. We investigate plasma enhanced chemical vapor deposited (PECVD) SiN x and atomic layer deposited AlO x as alternative nanolayers for the passivation layer in polysilicon tunnel contacts. We have fabricated p + poly-Si contacts with resistivities below 100 mΩ•cm 2 using these alternative metal oxide and nitride nanolayers. Initial passivation tests yielded low levels of passivation; however, a detailed understanding of the nanolayers elucidated the strategies to improve passivation significantly, achieving an implied open-circuit voltage (iV OC ) of 698 mV and dark saturation current density (J 0 ) of 34 fA/cm 2 for a p + poly-Si contact using a PECVD SiN x interlayer. These are among the best reported for nitride-based nanolayer tunneling contacts, with research into nitride-based tunneling contacts being still in its infancy.

show abstract

Electromechanical analysis of electrospun polymer fiber deposition

Chan,

Sadaf,

Gerrit Korvink

et al. 2023

Journal of Applied Physics

View full text Add to dashboard Cite

Electrospinning is an important technique to fabricate nanofibers. In recent years, near-field electrospinning (NFES) has been developed to enhance the control of nanofiber deposition compared to conventional electrospinning, achieved by reducing the operating distance and electric field. This enables the construction of high-aspect ratio 3D structures in a self-aligned, layer-by-layer manner. However, the alignment of fiber deposition can be hindered by charge accumulation in the polymer fibers. Furthermore, a theoretical understanding of the underlying fiber deposition mechanism is still lacking. Herein, we present a numerical model for studying the charge transport, dissipation, and accumulation of NFES polymer fiber deposition. The model reveals that the presence of a trapped state in polymeric materials imposes limitations on the quality of charged fiber deposition. Moreover, the effect of different substrate materials on charge dissipation in fiber deposition is studied. To validate the model, we compare the simulation results with NFES experiments, demonstrating qualitative agreement. We also analyze the effect of the fiber materials and experimental parameters on the printing quality. This model provides an approach to analyze and optimize the operating parameters of NFES to achieve precise and stable nanofiber deposition.

show abstract

Electrostatic Tuning of Ionic Charge in SiO₂ Dielectric Thin Films

Cited by 3 publications

References 72 publications

Ion‐Charged Dielectric Nanolayers for Enhanced Surface Passivation in High Efficiency Photovoltaic Devices

Ion‐Charged Dielectric Nanolayers for Enhanced Surface Passivation in High Efficiency Photovoltaic Devices

Hole-Selective SiN_x and AlO_x Tunnel Nanolayers for Improved Polysilicon Passivating Contacts

Electromechanical analysis of electrospun polymer fiber deposition

Contact Info

Product

Resources

About

Electrostatic Tuning of Ionic Charge in SiO2 Dielectric Thin Films

Cited by 3 publications

References 72 publications

Ion‐Charged Dielectric Nanolayers for Enhanced Surface Passivation in High Efficiency Photovoltaic Devices

Ion‐Charged Dielectric Nanolayers for Enhanced Surface Passivation in High Efficiency Photovoltaic Devices

Hole-Selective SiNx and AlOx Tunnel Nanolayers for Improved Polysilicon Passivating Contacts

Electromechanical analysis of electrospun polymer fiber deposition

Contact Info

Product

Resources

About

Electrostatic Tuning of Ionic Charge in SiO₂ Dielectric Thin Films

Hole-Selective SiN_x and AlO_x Tunnel Nanolayers for Improved Polysilicon Passivating Contacts