Heterojunction oxide thin-film transistors with unprecedented electron mobility grown from solution

Faber, Hendrik; Das, Satyajit; Lin, Yen‐Hung; Pliatsikas, N.; Zhao, Kui; Kehagias, Th.; Dimitrakopulos, G. P.; Patsalas, P.; Anthopoulos, Thomas D.

doi:10.1126/sciadv.1602640

Cited by 153 publications

(217 citation statements)

References 58 publications

(106 reference statements)

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“…It is important to note that the use of a heterostructure semiconductor channel has been demonstrated to increase the electron mobility in metal‐oxide transistors (e.g., ZnO/In 2 O 3 and InZnO/AlSnZnInO ) in addition to controlled modulation doping of ZnO/In 2 O 3 . These techniques have resulted in unprecedented improvements to charge transport . A review is dedicated to this topic for the design of metal‐oxide heterostructures exhibiting two‐dimensional transport behavior .…”

Section: Introductionmentioning

confidence: 99%

Use of high-k encapsulation to improve mobility in trap-limited metal-oxide semiconductors

Zeumault

Subramanian

2017

Phys. Status Solidi B

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Low‐temperature spray‐deposited ZnO films are encapsulated by insulating Ga2O3 films and the resulting electronic properties of heterostructure films and transistors are analyzed and compared to un‐encapsulated ZnO as a function of processing temperature. An enhancement in Hall mobility and field‐effect mobility is observed similar to when high‐k dielectrics are used as gate‐dielectrics in transparent conductive oxide thin‐film transistors except without the presence of undesirable device behavior such as gate‐leakage and hysteresis. Based on a recently proposed theory consisting of electron donation from high‐k dielectrics, work function measurements show that conditions for electron transfer from Ga2O3 to ZnO can be met by optimally‐tuning the deposition temperature of the respective films resulting in an effective doping which is qualitatively similar to modulation doping. As a result, TFTs composed of ZnO/Ga2O3 heterostructures exhibit greatly improved switching characteristics and electron transport relative to the otherwise poor performance of low‐temperature processed ZnO achieved through a simple modification to TFT device structure.

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Section: Introductionmentioning

confidence: 99%

Use of high-k encapsulation to improve mobility in trap-limited metal-oxide semiconductors

Zeumault

Subramanian

2017

Phys. Status Solidi B

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“…27 Despite the enhanced performance, the operating stability of HJ oxide TFTs has so far remained modest due to the persistent electronic defects present in the individual materials and at the heterointerfaces. [16][17][18] Since the operation 4 of these oxide HJ TFTs relies on the charge carriers transferred from the low-mobility layer on top of the high-mobility layer underneath, 4,26,27 the presence of electronic defects will deteriorate the device performance and its operational stability. Thus, reducing the electrontrap states within the HJ could potentially enhance the electron mobility and bias stability of the device.…”

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confidence: 99%

Hybrid organic–metal oxide multilayer channel transistors with high operational stability

et al. 2019

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Metal oxide thin-film transistors are fast becoming a ubiquitous technology for application in driving backplanes of organic light-emitting diode displays. Currently all commercial products rely on metal oxides processed via physical vapor deposition methods. Transition to simpler, higher throughput manufacturing methods such as solution-based processes, are currently been explored as cost-effective alternatives. However, developing printable oxide transistors with high carrier mobility and bias-stable operation has proved challenging. Here we show that hybrid multilayer channels composed of alternating ultra-thin layers (≤4 nm) of indium oxide, zinc oxide nanoparticles, ozone-treated polystyrene and a compact zinc oxide layer, all solution-processed in ambient atmosphere, can be used to create TFTs with remarkably high electron mobility (50 cm 2 /Vs) and record operational stability. Insertion of the ozone-treated polystyrene interlayer is shown to reduce the concentration of electron traps at the metal oxide surfaces and heterointerfaces. The resulting transistors exhibit dramatically enhanced bias stability over 24 h continuous operation and while subjected to large electric-field flux density (2.1×10 -6 C/cm 2 ) with no adverse effects on the electron mobility. Density functional theory calculations identify the origin of this enhanced stability as the passivation of the oxygen vacancy-related gap states due to interaction between ozonolyzed styrene moieties and the oxides. Our results sets new design guidelines for bias-stress resilient metal oxide transistors. Main textMoving away from sophisticated, capital intensive manufacturing processes, soluble semiconductors 1,2,3 not only promise to deliver devices with unusual physical characteristics and enhanced performance, but also trigger a paradigm shift in manufacturing philosophy by embracing scalable, cost-effective processes such as chemical spray pyrolysis, 4 ink-jet printing, 5 slot-die coating, 6 among others. As consequence the interest in solution-based manufacturing of consumer electronics is rapidly increasing with global tech giants investing heavily in emerging forms of printed electronics. 7 Among a variety of soluble electronic materials, oxide semiconductors offer a breadth of intriguing assets, including high charge carrier mobility, 8 optical transparency, 9 versatile synthesis, 10 low manufacturing cost 11 etc., the combination of which makes them ideal for use in a range of rapidly emerging applications in the field of printed electronics. Among them, thin-film transistor (TFTs) technologies are a priority for solution processable oxides as they promise to amplify the technological impact of their vacuum-grown counterparts 11 by reducing the manufacturing cost. For these reasons, continuous research efforts have been devoted to improving the operating characteristics of

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“…A further reduction in the work function (by >0.1 eV) is measured when the In 2 O 3 layer is inserted between ITO and ZnO. Since the impact of the In 2 O 3 layer on ITO's work function is minimal (<0.1 eV), the latter observation is attributed to the electron transfer from the conduction band minimum of ZnO to that of In 2 O 3 upon physical contact . The presence of the sharp chemical interface seen in Figure rules out the impact of material intermixing (alloying), hence making electron transfer the most likely process.…”

Section: Work Function Engineering In Bilayer In2o3/zno Etlsmentioning

confidence: 93%

“…Thicker In 2 O 3 layers were found to adversely affect the cell's performance when compared to the reference single‐layer ZnO ETL‐based devices. We attribute this to higher thickness of the In 2 O 3 layer which gives rise to an energetic barrier between the In 2 O 3 and the ZnO …”

Section: Ptb7‐th:pcbm Bulk Heterojunction Solar Cells Base On Bilayermentioning

confidence: 99%

Solution‐Processed In₂O₃/ZnO Heterojunction Electron Transport Layers for Efficient Organic Bulk Heterojunction and Inorganic Colloidal Quantum‐Dot Solar Cells

et al. 2018

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We report the development of a solution‐processed In2O3/ZnO heterojunction electron transport layer (ETL) and its application in high efficiency organic bulk‐heterojunction (BHJ) and inorganic colloidal quantum dot (CQD) solar cells. Study of the electrical properties of this low‐dimensional oxide heterostructure via field‐effect measurements reveals that electron transport along the heterointerface is enhanced by more than a tenfold when compared to the individual single‐layer oxides. Use of the heterojunction as the ETL in organic BHJ photovoltaics is found to consistently improve the cell's performance due to the smoothening of the ZnO surface, increased electron mobility and a noticeable reduction in the cathode's work function, leading to a decrease in the cells’ series resistance and a higher fill factor (FF). Specifically, non‐fullerene based organic BHJ solar cells based on In2O3/ZnO ETLs exhibit very high power conversion efficiencies (PCE) of up to 12.8%, and high FFs of over 70%. The bilayer ETL concept is further extended to inorganic lead‐sulphide CQD solar cells. Resulting devices exhibit excellent performance with a maximum PCE of 8.2% and a FF of 56.8%. The present results highlight the potential of multilayer oxides as novel ETL systems and lay the foundation for future developments.

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Heterojunction oxide thin-film transistors with unprecedented electron mobility grown from solution

Abstract: Engineering of solution-grown metal oxide heterointerfaces presents an alternative strategy for thin-film transistor development.

Cited by 153 publications

References 58 publications

Use of high-k encapsulation to improve mobility in trap-limited metal-oxide semiconductors

Use of high-k encapsulation to improve mobility in trap-limited metal-oxide semiconductors

Hybrid organic–metal oxide multilayer channel transistors with high operational stability

Solution‐Processed In₂O₃/ZnO Heterojunction Electron Transport Layers for Efficient Organic Bulk Heterojunction and Inorganic Colloidal Quantum‐Dot Solar Cells

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Heterojunction oxide thin-film transistors with unprecedented electron mobility grown from solution

Abstract: Engineering of solution-grown metal oxide heterointerfaces presents an alternative strategy for thin-film transistor development.

Cited by 153 publications

References 58 publications

Use of high-k encapsulation to improve mobility in trap-limited metal-oxide semiconductors

Use of high-k encapsulation to improve mobility in trap-limited metal-oxide semiconductors

Hybrid organic–metal oxide multilayer channel transistors with high operational stability

Solution‐Processed In2O3/ZnO Heterojunction Electron Transport Layers for Efficient Organic Bulk Heterojunction and Inorganic Colloidal Quantum‐Dot Solar Cells

Contact Info

Product

Resources

About

Solution‐Processed In₂O₃/ZnO Heterojunction Electron Transport Layers for Efficient Organic Bulk Heterojunction and Inorganic Colloidal Quantum‐Dot Solar Cells