Vertical Heterostructures for Transistors, Photodetectors, and Photovoltaic Devices

Delivers high current density2-5 orders of magnitude greater than current technologiesHigh on-off ratio1-2 orders of magnitude better than typical graphene devices at room temperatureHighly scalableFunctions at room temperature

Lower cost, higher performance transistors, photodetectors, and solar cellsReplace silicon in photovoltaic cellsCan be used with silicon complimentary metal-oxide superconductor (CMOS) logic circuits for high integration into electronic devicesFabrication of more complicated device functions, such as a complementary inverterUsage as a vertical thin film transistor for flexible displaysStorage of electrochemical energy

Since its isolation and increased production in 2003, graphene has been exploited for its remarkable strength, stability, and electron motility. The material has been used to improve a number of technologies including electronics, energy storage devices, and composites. Given the high conductivity of its ultra-thin sheets, it has potential to significantly reduce semiconductor size and improve power requirements. But despite the material’s exceptional qualities, graphene does not naturally have a band gap, and therefore cannot be switched off. Future use of graphene in semiconductor devices will require a mechanism that increases the on/off current ratio. UCLA researchers Drs. Xiangfeng Duan and Woojong Yu have developed a new technology that addresses the band gap problem of graphene. Their vertical field-effect transistor (VFET), which is an integration of vertically stacked multi-heterostructures of layered materials such as graphene, molybdenum disulfide (MoS2), and cobaltites (Bi2Sr2Co2O8), enables high current density by vertical current flow through overall semiconductor area with a large on/off current ratio. VFETs can deliver a current density 2-5 orders of magnitude and on/off ratios 1-2 orders of magnitude greater than existing graphene technologies.

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State Of Development

• The method has been validated both by computer simulation and experimental testing
• Future plans include optimization of the graphene-semiconductor junction and graphene transfer technique

Related Materials

Liu Y, Zhou H, Cheng R, Yu W, Huang Y, Duan X. Highly flexible electronics from scalable vertical thin film transistors. Nano Lett. 2014.
Yu WJ, Liu Y, Zhou H, et al. Highly efficient gate-tunable photocurrent generation in vertical heterostructures of layered materials. Nat Nanotechnol. 2013.

Additional Technologies by these Inventors

• Graphene Nanomesh As A Continuous Semiconducting Thin Film For Large Scale Field Effect Transistors
• Graphene Moisture-Resistive Membrane Cathode for Li-Air Battery in Ambient Conditions
• A Composite of Two Dimensional Material and One Dimensional Material as Transparent Conductor
• Conductor-Semiconductor Composite Films and Their Applications for High Performance Transistors
• Chemical Vapor Deposition Growth of the Large Single Crystalline Domains of Monolayer and Bilayer
• Graphene Based Catalysts for Biomimetric Generation of Antithrombotic Species
• Palladium Alloy Hydride Nano Materials
• High Performance Thin Films from Solution Processible Two-Dimensional Nanoplates
• Nanoscale Optical Voltage Sensors
• Ultrafine Nanowires As Highly Efficient Electrocatalysts
• Pore Size Engineering Of Porous Carbons Using Covalent Triazine Frameworks As Precursors
• The Method of Enhanced Pressure Sensing Performance for Pressure Sensors
• Very High Energy Density Silicide-Air Primary Batteries
• Wafer Scale Growth Of Large Arrays Of Perovskite Micro-Plate Crystals For Functional Electronics And Optoelectronics
• Three-Dimensional Holey Graphene Frameworks Based High-Performance Supercapacitors
• High Performance PtNiCuMo Electrochemical Catalyst
• Graphene Nanomesh As A Glucose Sensor
• Upconversion Plasmonic Mapping: A Direct Plasmonic Visualization And Spectrometer-Free Sensing Method
• Electrochemical Molecular Intercalation for Synthesis of Monolayer Atomic Crystal Molecular Superlattices

Tech ID/UC Case

23667/2013-363-0

Related Cases

2013-363-0

USA

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