Comparison of different types of interfacial oxides on hole-selective p+-poly-Si passivated contacts for high-efficiency c-Si solar cells

Guo, Xueqi; Liao, Mingdun; Rui, Zhe; Yang, Qing; Wang, Zhixue; Shou, Chunhui; Ding, Waner; Luo, Xijia; Cao, Y. H.; Jing, Xu; Fu, Liming; Zeng, Yuheng; Yan, Baojie; Ye, Jichun

doi:10.1016/j.solmat.2020.110487

Cited by 40 publications

(13 citation statements)

References 46 publications

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“…Afterward, a single-sided SiN x capping layer was deposited at 450 C using PECVD. [12,17,19] Then, the samples were subjected to the RTA processes. Finally, the samples were also subjected to 820 C N 2 annealing, 450 C N 2 annealing, and 450 C moisture/nitrogen annealing, respectively.…”

Section: Methodsmentioning

confidence: 99%

“…[8] The key structures of TOPCon SCs are comprised of an ultrathin silicon oxide (SiO x ) layer and a highly doped polysilicon (poly-Si) layer. The SiO x layer can be deposited by various methods, such as wet chemical oxidation, [3,5,9] ozone oxidation, [10,11] thermal oxidation, [11,12] plasma assistant oxidation, [12,13] and atomic layer deposition (ALD). [14,15] A high-quality SiO x layer requires a suitable thickness to provide an excellent level of chemical passivation while allowing charge-carrier-selective…”

mentioning

confidence: 99%

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Rapid‐Thermal‐Annealing‐Induced Passivation Degradation and Recovery of Polysilicon Passivated Contact with Czochralski and Cast Multicrystalline Silicon Substrates

Feng

Zeng

Yang

et al. 2021

Physica Status Solidi (a)

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Carrier-selective passivating contacts as one of the most promising technologies for high-efficiency crystalline silicon (c-Si) solar cells (SCs) have been widely exploited for applications in heterojunction SCs, such as intrinsic thin hydrogenated amorphous silicon (a-Si:H) passivation layer (HIT) [1,2] and tunnel oxide passivated contact (TOPCon) SCs. [3][4][5][6] The remarkable advantages of a high open-circuit voltage (V oc ), a low-temperature coefficient, and a simple manufacturing procedure are usually endowed to HIT SCs. However, this type of HIT SC suffers from intrinsic drawbacks as well; for example, it is not compatible with the current mainstream passivated emitter and rear contact (PERC) technology, and it often requires capital-intensive equipment to produce the devices. In contrast, TOPCon technology has the potential to evade these issues, which thus has attracted significant attention in the global photovoltaic community. Apart from the advantage of the high compatibility with the PERC production lines, which could radically reduce manufacturing costs, an additional advantage of high potential efficiencies due to the excellent passivating contacts properties is also realized for TOPCon SCs. Remarkable progress in promoting the efficiency of this type of TOPCon device have been achieved, yielding a lab-scale record efficiency of 26.1%, [7] and a large-area industrial efficiency of 24.58%. [6] It is worthy noting that high-efficiency TOPCon SCs are usually produced using low-cost multicrystalline silicon (mc-Si) wafers, especially for the cast multicrystalline silicon (cast-mc-Si) wafers. [8] The key structures of TOPCon SCs are comprised of an ultrathin silicon oxide (SiO x ) layer and a highly doped polysilicon (poly-Si) layer. The SiO x layer can be deposited by various methods, such as wet chemical oxidation, [3,5,9] ozone oxidation, [10,11] thermal oxidation, [11,12] plasma assistant oxidation, [12,13] and atomic layer deposition (ALD). [14,15] A high-quality SiO x layer requires a suitable thickness to provide an excellent level of chemical passivation while allowing charge-carrier-selective

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Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

Rapid‐Thermal‐Annealing‐Induced Passivation Degradation and Recovery of Polysilicon Passivated Contact with Czochralski and Cast Multicrystalline Silicon Substrates

Feng

Zeng

Yang

et al. 2021

Physica Status Solidi (a)

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“…For p‐type solar cells with p‐type passivating rear contacts, work often focuses on simulation [ 12–15 ] as certain input parameters can be obtained from test structures or characterization of test structures. [ 16 ] However, the actual demonstration of a solar cell with screen‐printed metallization that comes near the determined efficiencies in simulation can be challenging, for the reasons explained earlier, resulting only in a limited amount of publications. [ 17,18 ] Alternatively, in other contributions, physical vapor deposition (PVD) is used often for rear metallization [ 19–22 ] due to the noninvasiveness of this technology.…”

Section: Introductionmentioning

confidence: 99%

Progress in p‐type Tunnel Oxide‐Passivated Contact Solar Cells with Screen‐Printed Contacts

et al. 2021

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Herein, an update on the work on high‐efficiency p‐type solar cells with p‐type‐passivating rear contacts formed by low‐pressure chemical vapor deposition and screen‐printed contacts is given. It is shown that thin polysilicon layers enable a high level of surface passivation but do show increased contact resistivity and especially contact recombination. Commercially available pastes and dependence of contact resistivity and contact recombination on polylayer thickness and firing set temperature are investigated. For 240 nm‐thick poly‐Si layers, the values down to 4 mΩ cm2 and 60 fA cm−2 are observed. For the presented process sequence, improved hydrogenation as one possibility to increase the passivation quality of the passivating contact structure is identified. Implementing all findings into a final solar cell, a maximum total area conversion efficiency of 21.2% is reported.

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“…[3] The dielectric materials, such as Al 2 O 3 and SiO X , have been attempted as alternative tunnel layers instead of a-Si:H. [18][19][20] Among them, SiO X has been successfully used in tunnel oxide passivating contact (TOPCon) solar cells. [21][22][23] The SiO X can be obtained by thermal growth in an oxygen atmosphere, [24] HNO 3 wet chemical oxidation, ozonewater wet chemical oxidation, and ultraviolet ozone (UV/O 3 ) dry chemical oxidation, etc. [25] During the thermal evaporation of MoO X , WO X , and V 2 O X , a thin layer of SiO X is formed simultaneously due to the redox reaction with Si.…”

Section: Introductionmentioning

confidence: 99%

Improved V₂O_X Passivating Contact for p‐Type Crystalline Silicon Solar Cells by Oxygen Vacancy Modulation with a SiO_X Tunnel Layer

Yang

et al. 2021

Adv Materials Inter

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passivating contacts have achieved a PCE up to 25.11%. [2] However, the a-Si:H involves capital intensive deposition process and toxic gas precursors, [3] and its relatively high parasitic absorption limits further improvements in device performance. [4,5] To address the above issues with lower parasitic absorption and process cost, alternative carrier-selective contacts based on wide bandgap transition metal oxides (TMOs) have triggered extensive research interest in the photovoltaic community. [6] TMOs featuring high work functions (Φ >5.5 eV) such as MoO X , [7][8][9] V 2 O X , [10][11][12] and WO X [13] are capable of inducing either an inversion layer on n-type silicon (n-Si) or an accumulation layer of holes on p-type silicon (p-Si), thus rendering selective hole extraction. [7,14] The c-Si solar cell with a full-area MoO X contact is one of the most successful examples, which has obtained a record PCE of 23.5%. [15] Compared with MoO X , V 2 O X , with properly tuned oxygen vacancies, has a higher work function and can induce a greater upward band bending on the c-Si surface, resulting in a superior fieldeffect passivation quality. [14,16] The highest PCE of n-Si cells with V 2 O X hole transport layer (HTL) is 21.6% up to now. [12] Inmetal oxide (TMO) thin films featuring tunable work function, high transmittance, and simple fabrication process are expected to serve as carrier-selective transport layers for high-efficiency crystalline silicon (c-Si) solar cells. TMOs are prone to reaction or elemental migration with adjacent materials, which leads to uncontrollable optical and electrical properties. In this work, V 2 O X passivating contact, a promising hole transport layer (HTL) thanks to its high work function, is investigated and implemented in p-type c-Si solar cells. An ultrathin SiO X tunnel layer is intentionally introduced by UV/O 3 pretreatment to suppress the redox reaction at c-Si/V 2 O X interface. Both saturation current density and contact resistance are reduced with the presence of UV-SiO X due to the well tunned oxygen vacancies in SiO X and V 2 O X thin films. The power conversion efficiency (PCE) based on p-Si/UV-SiO X /V 2 O X /Ag rear contact achieves 21.01% with an increased open-circuit voltage of 635 mV and fill factor (FF) of 83.25%.

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Comparison of different types of interfacial oxides on hole-selective p+-poly-Si passivated contacts for high-efficiency c-Si solar cells

Cited by 40 publications

References 46 publications

Rapid‐Thermal‐Annealing‐Induced Passivation Degradation and Recovery of Polysilicon Passivated Contact with Czochralski and Cast Multicrystalline Silicon Substrates

Rapid‐Thermal‐Annealing‐Induced Passivation Degradation and Recovery of Polysilicon Passivated Contact with Czochralski and Cast Multicrystalline Silicon Substrates

Progress in p‐type Tunnel Oxide‐Passivated Contact Solar Cells with Screen‐Printed Contacts

Improved V₂O_X Passivating Contact for p‐Type Crystalline Silicon Solar Cells by Oxygen Vacancy Modulation with a SiO_X Tunnel Layer

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Comparison of different types of interfacial oxides on hole-selective p+-poly-Si passivated contacts for high-efficiency c-Si solar cells

Cited by 40 publications

References 46 publications

Rapid‐Thermal‐Annealing‐Induced Passivation Degradation and Recovery of Polysilicon Passivated Contact with Czochralski and Cast Multicrystalline Silicon Substrates

Rapid‐Thermal‐Annealing‐Induced Passivation Degradation and Recovery of Polysilicon Passivated Contact with Czochralski and Cast Multicrystalline Silicon Substrates

Progress in p‐type Tunnel Oxide‐Passivated Contact Solar Cells with Screen‐Printed Contacts

Improved V2OX Passivating Contact for p‐Type Crystalline Silicon Solar Cells by Oxygen Vacancy Modulation with a SiOX Tunnel Layer

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Improved V₂O_X Passivating Contact for p‐Type Crystalline Silicon Solar Cells by Oxygen Vacancy Modulation with a SiO_X Tunnel Layer