Effects of silicon surface defects on the graphene/silicon Schottky characteristics

Wong, Hei; Anwar, Muhammad Abid; Dong, Shurong

doi:10.1016/j.rinp.2021.104744

Cited by 8 publications

(19 citation statements)

References 36 publications

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“…[23] It has been shown that the Schottky barrier height strongly depends on the number of surface states at the metal/semiconductor interface. [83,84] For instance, Kasahara et al has proposed that the Schottky barrier height highly depends on the contact area of the Fe 3 Si/Ge junction due to the different number of interfacial defects. [85] The unequal Schottky barrier heights for AS-MoS 2 device can be explained by the unequal number of MoS 2 /Cr interface states at two sides, which could be attributed to the presence of S-vacancies.…”

Section: Resultsmentioning

confidence: 99%

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Flexible High‐Performance Photovoltaic Devices based on 2D MoS₂ Diodes with Geometrically Asymmetric Contact Areas

Abnavi

Ahmadi

Ghanbari

et al. 2022

Adv Funct Materials

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Optoelectronic performance of 2D transition metal dichalcogenides (TMDs)‐based solar cells and self‐powered photodetectors remain limited due to fabrication challenges, such as difficulty in doping TMDs to form p–n junctions. Herein, MoS2 diodes based on geometrically asymmetric contact areas are shown to achieve a high current rectification ratio of ≈105, facilitating efficient photovoltaic charge collection. Under solar illumination, the device demonstrates a high open‐circuit voltage (Voc) of 430 mV and a short‐circuit current density (Jsc) of −13.42 mA cm−2, resulting in a high photovoltaic power conversion efficiency (PCE) of 3.16%, the highest reported for a lateral 2D solar cell. The diodes also show a high photoresponsivity of 490.3 mA W−1, and a large photo detectivity of 4.05 × 1010 Jones, along with a fast response time of 0.8 ms under 450 nm wavelength at zero bias for self‐powered photodetection applications. The device transferred on a flexible substrate shows a high photocurrent and PCE retentions of 94.4%, and 88.2% after 5000 bending cycles at a bending radius of 1.5 cm, respectively, demonstrating robustness for flexible optoelectronic applications. The simple fabrication process, superior photovoltaic properties, and high flexibility suggests that the geometrically asymmetric MoS2 device architecture is an excellent candidate for flexible photovoltaic and optoelectronic applications.

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Section: Resultsmentioning

confidence: 99%

“…It has been shown that the Schottky barrier height strongly depends on the number of surface states at the metal/semiconductor interface. [ 83,84 ] For instance, Kasahara et al. has proposed that the Schottky barrier height highly depends on the contact area of the Fe 3 Si/Ge junction due to the different number of interfacial defects.…”

Section: Resultsmentioning

confidence: 99%

Flexible High‐Performance Photovoltaic Devices based on 2D MoS₂ Diodes with Geometrically Asymmetric Contact Areas

Abnavi

Ahmadi

Ghanbari

et al. 2022

Adv Funct Materials

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“…The main challenge is to carry out a precise reduction process (using different reducing agents or reduction conditions), with the possibility of controlling both the reduction degree (the OFGs’ content) and the selectivity of the key OFGs’ removal [ 11 , 33 ]. Moreover, when dealing with applications in different optoelectronic and energy conversion and electrochemical storage areas the other very important issue is that the reduction process must be compatible with on-chip integration [ 9 , 34 , 35 , 36 , 37 ].…”

Section: Introductionmentioning

confidence: 99%

Effect of Electrolytic Medium on the Electrochemical Reduction of Graphene Oxide on Si(111) as Probed by XPS

et al. 2021

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The wafer-scale integration of graphene is of great importance in view of its numerous applications proposed or underway. A good graphene–silicon interface requires the fine control of several parameters and may turn into a high-cost material, suitable for the most advanced applications. Procedures that can be of great use for a wide range of applications are already available, but others are to be found, in order to modulate the offer of different types of materials, at different levels of sophistication and use. We have been exploring different electrochemical approaches over the last 5 years, starting from graphene oxide and resulting in graphene deposited on silicon-oriented surfaces, with the aim of understanding the reactions leading to the re-establishment of the graphene network. Here, we report how a proper choice of both the chemical environment and electrochemical conditions can lead to a more controlled and tunable graphene–Si(111) interface. This can also lead to a deeper understanding of the electrochemical reactions involved in the evolution of graphene oxide to graphene under electrochemical reduction. Results from XPS, the most suitable tool to follow the presence and fate of functional groups at the graphene surface, are reported, together with electrochemical and Raman findings.

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“…17,18 For a larger bias, lnJ DT ∞ V. If the applied voltage is much smaller than the barrier height, the slope of lnJ DT versus voltage plot is a linear function of the applied voltage, 18 or one can fit the tunneling current at low voltage with a quadratic equation. It should be noted that interface and oxide traps could assist the current conduction in the MIS structure via the Poole−Frenkel emission; 12,16 however, no notable excess current was observed in the present plot. This is because the insulating film was so thin (only 2 nm, which is below the direct tunneling limit) that the electrons could readily tunnel through the thin film before being captured by the defects.…”

Section: Resultsmentioning

confidence: 52%

“…Unlike the metal/Si interface, where the silicon dangling bond can effectively be passivated with the metal, the graphene/Si contact is weakly bonded by van der Waal forces and the Si surface dangling bonds covered by graphene are electrically active and can trap both electrons and holes . Growing a high-quality insulating layer could be one of the effective methods in passivating the silicon dangling bonds and enhancing the power conversion efficiency (PCE) of the solar cells significantly. − In the work reported in ACS Appl. Energy Mater.…”

Section: Introductionmentioning

confidence: 99%

Comment on “Enhanced and Passivated Co-Doping Effect of Organic Molecule and Bromine on Graphene/HfO₂/Silicon Metal-Insulator-Semiconductor (MIS) Schottky Junction Solar Cells”

Wong

2024

ACS Appl. Energy Mater.

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Graphene/Silicon Schottky junction was found to have a high potential for photovoltaic applications. In ACS Appl. Energy Mater. 2022, 5, 9, 10509−10517, Kadam and co-workers proposed high-performance solar cells based on graphene/HfO 2 / silicon MIS structure with certain doping and passivation. The thin HfO 2 layer passivates the surface silicon dangling bonds, reduces the trapping of photogenerated carriers, and enhances the power conversion efficiency and long-term stability of the solar cells. However, we note some inaccuracies in applying the Schottky emission model and extracting the Schottky barrier heights from the current−voltage characteristics. Here we propose that the current−voltage behavior of the Gr/HfO 2 /Si MIS structure is better explained by direct tunneling and the Fowler−Nordheim tunneling mechanisms. Instead of being governed by the Schottky barrier only, we suggest that the current−voltage characteristics should be mainly governed by the barrier height between the Si/HfO 2 and Gr/HfO 2 interface as well as the insulator thickness. With the exact proposed mechanisms, we consistently explain some unexplained phenomena, such as the current enhancement at the large forward voltage and the effects of covering the devices with a thick insulating layer in their devices. These mechanisms suggest a different way for further device performance improvement. The thickness of the dielectric film as well as its band offset with Si are important parameters for process optimization.

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Effects of silicon surface defects on the graphene/silicon Schottky characteristics

Cited by 8 publications

References 36 publications

Flexible High‐Performance Photovoltaic Devices based on 2D MoS₂ Diodes with Geometrically Asymmetric Contact Areas

Flexible High‐Performance Photovoltaic Devices based on 2D MoS₂ Diodes with Geometrically Asymmetric Contact Areas

Effect of Electrolytic Medium on the Electrochemical Reduction of Graphene Oxide on Si(111) as Probed by XPS

Comment on “Enhanced and Passivated Co-Doping Effect of Organic Molecule and Bromine on Graphene/HfO₂/Silicon Metal-Insulator-Semiconductor (MIS) Schottky Junction Solar Cells”

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Effects of silicon surface defects on the graphene/silicon Schottky characteristics

Cited by 8 publications

References 36 publications

Flexible High‐Performance Photovoltaic Devices based on 2D MoS2 Diodes with Geometrically Asymmetric Contact Areas

Flexible High‐Performance Photovoltaic Devices based on 2D MoS2 Diodes with Geometrically Asymmetric Contact Areas

Effect of Electrolytic Medium on the Electrochemical Reduction of Graphene Oxide on Si(111) as Probed by XPS

Comment on “Enhanced and Passivated Co-Doping Effect of Organic Molecule and Bromine on Graphene/HfO2/Silicon Metal-Insulator-Semiconductor (MIS) Schottky Junction Solar Cells”

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Product

Resources

About

Flexible High‐Performance Photovoltaic Devices based on 2D MoS₂ Diodes with Geometrically Asymmetric Contact Areas

Flexible High‐Performance Photovoltaic Devices based on 2D MoS₂ Diodes with Geometrically Asymmetric Contact Areas

Comment on “Enhanced and Passivated Co-Doping Effect of Organic Molecule and Bromine on Graphene/HfO₂/Silicon Metal-Insulator-Semiconductor (MIS) Schottky Junction Solar Cells”