CNT FIELD EMISSION CATHODE CATALOG April 2014 Version 1 1
TABLE OF CONTENTS: 1. ABBREVIATIONS... 2 2. INTRODUCTION... 3 3. PRODUCT AT A GLANCE... 6 4. CARBON NANOTUBE (CNT) CATHODE INFORMATION CHART*... 7 5. HOW TO READ OUR CATALOG NUMBERS... 8 6. DIODE CNT CATHODES... 9 CATALOG NUMBER: XRC-D01-SSD-R1 10... 9 CATALOG NUMBER: XRC-D01-SSP-C10 10... 10 CATALOG NUMBER: XRC-D01-MOC-C10 10... 11 CATALOG NUMBER: XRC-D01-SSC-C10 10... 11 CATALOG NUMBER: XRC-D01-SSC-C2.5 2.5... 13 CATALOG NUMBER: XRC-D01-MOR-R2 15... 14 CATALOG NUMBER: XRC-D01-SSR-R2 15... 14 7. TRIODE CNT CATHODES... 15 CATALOG NUMBER: XRC-T01-SSC-C2.5 2.5... 15 CATALOG NUMBER: XRC-T01-MOC-C10 10... 16 CATALOG NUMBER: XRC-T01-SSR-R3 10... 17 CATALOG NUMBER: XRC-T01-SSC-R3 10... 18 CATALOG NUMBER: XRC-T03-MO-R2 15... 19 8. CUSTOMIZED CNT CATHODES... 20 9. PRICING AND LEAD TIME... 20 10. CONTACT INFORMATION... 21 1. ABBREVIATIONS : XinRay Carbon nanotube(s): CNT(s) Chemical vapor deposition: CVD Few wall carbon nanotube(s): FWNT(s) Electron beam: e-beam Electron(s): e - Stainless steel: SS Molybdenum: Mo Tungsten: W Millimeter(s): mm Centimeter(s): cm Micrometer(s): µm Ampere(s): A Milliampere(s): ma Volt(s): V Direct current: DC Height: H Length: L Width: W Radius: R Diameter: Ø Transmission electron microscope: TEM Scanning electron microscope: SEM Hour(s): hr Second(s): s Current versus Voltage: I-V 2
2. INTRODUCTION ABOUT XINRAY: is specialized in making high quality CNT and CNT-based field emission cathodes for a wide variety of applications, including field emission x-ray tubes and field emission displays. XINRAY S CNT FIELD EMISSION CATHODE TECHNOLOGIES: XinRay s CNT-based field emission cathodes are fabricated using its proprietary postdeposition technologies [1]. The technologies utilize optimized CNTs with enhanced field emission properties as electron field emitters for the cathodes [1, 2]. WHAT IS UNIQUE ABOUT XINRAY S CNT FIELD EMISSION CATHODES? XinRay s CNT field emission cathodes have superior field emission performance. The core of the CNT cathodes is the CNT field emission materials. At XinRay, CNT materials are produced using its proprietary CVD process and have an excellent structural integrity [2]. Both of XinRay s CNT materials and CNT field emission cathodes have been optimized over many years based on comprehensive research and development efforts to achieve optimal field emission performance from the CNT cathodes. WHAT ARE FIELD EMISSION GRADE CARBON NANOTUBES OR FEW WALL NANOTUBES (FWNT)? The term Field Emission Grade Carbon Nanotubes or Few Wall Carbon Nanotubes (FWNT) refers to a class of CNT developed by XinRay and its collaborator for field emission applications [2]. The FWNT presents superior field emission properties compared with other CNT materials, including lower turn on field, higher emission current, and better emission stability. WHAT IS A DIODE CNT CATHODE? A diode CNT cathode (Figure 1) includes CNT field emitters deposited on a conducting substrate. The diode CNT cathode does not have a gate electrode and therefore cannot generate an e-beam directly. To extract electrons from the diode CNT cathode, a gate electrode or an anode needs to be integrated with the diode CNT cathode. The diode CNT cathode is simple and
cheap to produce. It is often used by customers who have their own electron gun structure (e.g., gate, anode and focusing electrodes, etc.). WHAT IS A TRIODE CNT CATHODE? A triode CNT cathode (Figure 2) includes a diode CNT cathode and an integrated gate electrode. Compared with the diode CNT cathode, it is much easier to use because an e-beam can be generated directly from a triode CNT cathode when a positive voltage differential is applied between the gate and the CNT emitters. WHAT IS THE PARALLEL PLATE TEST? The parallel plate test is a diode test that XinRay uses to evaluate the field emission properties of diode CNT cathodes. In the parallel plate test (Figure 1), a flat metal plate is used as anode and placed in parallel above a diode CNT cathode. To extract an e-beam from the cathode, a positive voltage differential should be applied between the anode and the diode CNT cathode. All the electrons emitted from the CNT cathode are collected by the anode. The parallel plate geometry is the most efficient way to apply a uniform electric field on the CNT emitters. Therefore it is typically used to measure the intrinsic performance of the CNT emitters. WHAT IS THE MESH TEST? The mesh test is similar to the parallel plate test except that a mesh instead of a metal plate is used as anode and placed in parallel above a diode CNT cathode (Figure 3). The mesh test is also a diode test. The electric field applied on the CNT emitters in the mesh test is not as uniform as in the parallel plate test, especially when the gap between the CNT emitters and the anode is very small. However, mesh is often required in actual uses of CNT cathodes. Therefore mesh test yields results closer to the reality than the parallel plate test. WHAT IS THE TRIODE TEST? The triode test simulates actual working environments of a CNT cathode and produces results closest to the reality among all the tests discussed herein. In the triode test (Figure 2), a gate mesh is place at close proximity to the CNT emitters that enables extraction of
electrons from the CNT emitters at a small positive voltage differential between the CNT the gate mesh and the CNT emitters. An anode is placed at a relatively large distance from the gate mesh and a large positive voltage differential is applied between the gate mesh and the anode. Part of the emitted electrons will be intercepted by the gate mesh while the rest will escape from the mesh gate and eventually be collected by the anode. REFERENCES: 1. Fabrication and electron field emission properties of carbon nanotube films by electrophoretic deposition, Bo Gao, Guozhen Yue, Qi Qiu, Yuan Cheng, Hideo Shimoda, Les Fleming and Otto Zhou, Advanced Materials, 2001, 13 (23), 1770-1774. 2. Fabrication of Small Diameter Few-Walled Carbon Nanotubes with Enhanced Field Emission Property, Cheng Qian, Hang Qi, Bo Gao, Yuan Cheng, Qi Qiu, Lu-Chang Qin, Otto Zhou, and Jie Liu, Journal of Nanoscience and Nanotechnology, 2006, 6, 1346 1349. 3. Method of synthesizing small-diameter carbon nanotubes with electron field emission properties, J. Liu, C. S. Du, C. Qian, B. Gao, Q. Qiu, and O. Zhou, US Patent Number 7618300 issued November 17, 2009.
3. PRODUCT AT A GLANCE A B C D E Figure captions: A. A TEM image showing the structure of CNT raw materials used by XinRay for making CNT cathodes. B. A customized diode CNT cathode with 13 individual CNT emitters. C. A SEM image showing the typical surface morphology of XinRay s CNT cathodes. D. A customized triode CNT cathode with 5 individual CNT emitters. E. A field emission image showing the uniform electron emission from one of XinRay s diode CNT cathodes with 1 cm in diameter emission area. 6
4. CARBON NANOTUBE (CNT) CATHODE INFORMATION CHART* Catalog number XRC-D01-SSD- R1 10 XRC-D01-SSP- C10 10 XRC-D01-SSC- C2.5 2.5 XRC-D01- MOC-C10 10 XRC-D01-SSC- C10 10 XRC-D01- MOR-R2 15 XRC-D01-SSR- R2 15 XRC-T01-SSC- C2.5 2.5 XRC-T01- MOC-C10 10 XRC-T01-SSR- R3 10 XRC-T01-SSC- R3 10 XRC-T03- MOR-R2 15 Cathode type Diode (w/o gate) Diode (w/o gate) Diode (w/o gate) Diode (w/o gate) Diode (w/o gate) Diode (w/o gate) Diode (w/o gate) Triode (with gate) Triode (with gate) Triode (with gate) Triode (with gate) Triode (with gate) Number of emitters Substrate material Emission area shape & size 1 SS 304 Rectangle 1 mm 10 mm 1 SS 304 Circle 10 mm 10 mm 1 SS 304 Circle 2.5 mm 2.5 mm 1 Mo Circle 10 mm 10 mm 1 SS 304 Circle 10 mm 10 mm 1 Mo Rectangle 2 mm 15 mm 1 SS 304 Rectangle 1 mm 10 mm 1 SS 304 Circle 2.5 mm 2.5 mm 1 Mo Circle 10 mm 10 mm 1 SS 304 Rectangle 3 mm 10 mm 1 SS 304 Rectangle 3 mm 10 mm 3 Mo Rectangle 2 mm 15 mm Current density 5 ma/cm 2 DC 2 A/cm 2 Pulse 2 ma/cm 2 DC 1.5 A/cm 2 Pulse 5 ma/cm 2 DC 2 A/cm 2 Pulse 2 ma/cm 2 DC 1.5 A/cm 2 Pulse 2 ma/cm 2 DC 1.5 A/cm 2 Pulse 5 ma/cm 2 DC 5 A/cm 2 Pulse 5 ma/cm 2 DC 2 A/cm 2 Pulse 5 ma/cm 2 DC 0.5 A/cm 2 Pulse 2 ma/cm 2 DC 1.8 A/cm 2 Pulse 2 ma/cm 2 DC 2 A/cm 2 Pulse 2 ma/cm 2 DC 2 A/cm 2 Pulse 2 ma/cm 2 DC 3.5 A/cm 2 Pulse Built-in gate No No No No No No No Yes Yes Yes Yes Yes *Please see the section for each CNT cathode for more detailed information about the cathode! The chart above only lists XinRay s standard CNT cathodes. Contact XinRay for information about customized CNT cathodes! Sales & Customer Service: P.O. Box 12848 7020 Kit Creek Road, Suite 210 Research Triangle Park, NC 27709 USA Tel: 1-919-313-9685 ext. 511 1-919-423-1832 Fax: 1-919-313-9686 Email: bgao@xinraysystems.com xinraysystems@xinraysystems.com 7
5. HOW TO READ OUR CATALOG NUMBERS Catalog number = Manufacturer & product name + Type of cathode & number of emitters + Substrate material & shape + Shape and size of the emission area -------------------------------------------------------------------------------------------------------------------------- Manufacturer & product name: XRC = XinRay CNT field emission cathode Type of cathode & number of emitters: D = Diode cathode) / T = Triode cathode ## = Number of emitters Substrate material & shape: SSD = SS 304 disk substrate SSP = SS 304 plate substrate SSC = SS 304 cylinder substrate MOC = Mo cylinder substrate MOR = Mo rectangular prism substrate Shape and size of the emission area: R# # = Emission area is a rectangle-shaped area with #mm in width and #mm in length C# # = Emission area is a circle-shaped area with #mm in diameter C#.# #.# = Emission area is a circle-shaped area with #.#mm in diameter circle E# # = Emission area is an ellipse-shaped area with #mm minor axis and #mm major axis E#.# #.# = Emission area is an ellipse-shaped area with #.#mm minor axis and #.#mm major axis -------------------------------------------------------------------------------------------------------------------------- For example: Catalog number XRC-D01-SSD-R1 10 means: XinRay CNT field emission cathode Diode cathode with a single emitter Stainless steel disk substrate Emission area is a rectangle-shape area with 1 mm in width and 10 mm in length. -------------------------------------------------------------------------------------------------------------------------- 8
6. DIODE CNT CATHODES CATALOG NUMBER: XRC-D01-SSD-R1 10 CHARACTERISTICS: Cathode type: Diode cathode Substrate: SS 304 Number of emitters: 1 Emission area: 1 mm 12 mm (standard)* Emission current density**: 5 ma/cm 2 in DC mode Up to 2 A/cm 2 in pulse mode Low threshold field: <2 V/µm @ 10 ma/cm 2 (parallel plate test) *Contact XinRay for information about cathodes with non-standard emission areas **Actual results depend strongly on the operating environment (10-8 Torr or better vacuum level is strongly recommended for stable operation of the CNT cathodes) **The thermal load on cathode, gate and anode is much higher in DC mode than in pulse mode. Therefore the stable emission current achievable in DC mode is much smaller than in pulse mode. FIELD EMISSION PROPERTIES: Single emitter Low current test Parallel plate test Gap distance: 180 µm DC mode (100% duty cycle) 15 ma/cm 2 @ <2 V/µm Good cathode to cathode consistency 9
4. DIODE CNT CATHODES CATALOG NUMBER: XRC-D01-SSP- C10 10 CHARACTERISTICS: Cathode type: Diode cathode Substrate: SS 304 Number of emitters: 1 Emission area: 1 cm or 1.27 cm in diameter (standard)* Emission current density**: 2 ma/cm 2 in DC mode 1.5 A/cm 2 in pulse mode Low threshold field: <2 V/µm @ 10 ma/cm 2 (parallel plate test) *Contact XinRay for information about cathodes with non-standard emission areas **Actual results depend strongly on the operating environment (10-8 Torr or better vacuum level is strongly recommended for stable operation of the CNT cathodes) FIELD EMISSION PROPERTIES: Single emitter Low current field emission image test Parallel plate test Pulse mode (10% duty) Current density: 8 ma/cm 2 Anode voltage: 1300 V Cathode to anode gap: 1 mm Single emitter Low current test Parallel plate test Pulse mode (10% duty) 10
Single emitter Low current test Parallel plate test DC mode (100% duty) Constant current mode (the emission current of the cathode is kept as constant by adjusting the anode voltage) Excellent emission stability (anode voltage ramp up rate is only about 0.18 V/hr to maintain the constant emission current density) 4. DIODE CNT CATHODES CATALOG NUMBER: XRC-D01-MOC-C10 10 CATALOG NUMBER: XRC-D01-SSC-C10 10 CHARACTERISTICS: Cathode type: Diode cathode Substrate: Mo or SS 304 Number of emitters: 1 Emission area: 10 mm in diameter (standard)* Emission current density**: 2 ma/cm 2 in DC mode 1.5 A/cm 2 in pulse mode Low threshold field: <2 V/µm @ 10 ma/cm 2 (parallel plate test) *Contact us for information about cathodes with non-standard emission areas **Actual results depend strongly on the operating environment (10-8 Torr or better vacuum level is strongly recommended for stable operation of the CNT cathodes) 11
FIELD EMISSION PROPERTIES: Single emitter High current test Parallel plate test Pulse mode (0.1% duty) Single emitter High current test Parallel plate test Pulse mode (0.1% duty) Constant voltage mode (voltage between the cathode and anode remains the same during testing) Excellent emission stability (the emission current remains almost unchanged during the whole testing process) 12
4. DIODE CNT CATHODES CATALOG NUMBER: XRC-D01-SSC-C2.5 2.5 CHARACTERISTICS: Cathode type: Diode cathode Substrate: SS 304 or Mo Number of emitters: 1 Emission area: 1 mm or 2.5 mm in diameter (standard)* Emission current density**: 5 ma/cm 2 in DC mode Up to 2 A/cm 2 in pulse mode Low threshold field: <3.5 V/µm @ 10 ma/cm 2 (mesh test) *Contact XinRay for information about cathodes with non-standard emission areas **Actual results depend strongly on the operating environment (10-8 Torr or better vacuum level is strongly recommended for stable operation of the CNT cathodes) FIELD EMISSION PROPERTIES: Single emitter Low current test Mesh test Pulse mode 1% duty cycle 1 Hz 10 ms pulse width 13
4. DIODE CNT CATHODES CATALOG NUMBER: XRC-D01-MOR-R2 15 CATALOG NUMBER: XRC-D01-SSR-R2 15 CHARACTERISTICS: Cathode type: Diode cathode Substrate: Mo or SS 304 Number of emitters: 1 Emission area: 2 mm 15 mm or 1 mm 20 mm (standard size)* Emission current density**: 5 ma/cm 2 in DC mode Up to 5 A/cm 2 in diode mode and pulse mode Low threshold field: <3 V/µm @ 10 ma/cm 2 (parallel plate test) *Contact us for information about cathodes with non-standard emission areas **Actual results depend strongly on the operating environment (10-8 Torr or better vacuum level is strongly recommended for stable operation of the CNT cathodes) FIELD EMISSION PROPERTIES: Single emitter Low current test Parallel plate test DC mode (100% duty) 3 different I-V cycles 14
Single emitter High current test Parallel plate test Pulse mode (0.1% duty) Constant current mode (anode voltage is adjusted to maintain the constant emission current) 5 A/cm 2 achieved with excellent stability 7. TRIODE CNT CATHODES CATALOG NUMBER: XRC-T01-SSC-C2.5 2.5 CHARACTERISTICS: Cathode type: Triode cathode Number of emitters: 1 Cathode substrate & Body: SS 304 Gate: W Gate to cathode gap: ~200 µm Emission area: 1 mm or 2.5 mm in diameter (standard)* Emission current density**: Up to 5 ma/cm 2 in DC mode Up to 500 ma/cm 2 in pulse mode Electron transmission rate: ~70% Low threshold field: <3.5 V/µm @ 10 ma/cm 2 (triode test) *Contact us for information about cathodes with non-standard emission areas **Actual results depend strongly on the operating environment (10-8 Torr or better vacuum level is strongly recommended for stable operation of the CNT cathodes) 15
FIELD EMISSION PROPERTIES: Single emitter Low current test Triode test DC mode (100% duty) Electron transmission rate: 70% 5. TRIODE CNT CATHODES CATALOG NUMBER: XRC-T01-MOC-C10 10 CHARACTERISTICS: Cathode type: Triode cathode Number of emitters: 1 Cathode substrate & Body: Mo / SS 304 Gate: W Gate to cathode gap: ~200 µm Emission area: 10 mm in diameter (standard)* Emission current**: 2 ma/cm 2 in DC mode Up to 1.8 A/cm 2 in pulse mode Electron transmission rate: ~60% Low threshold field: <3.5 V/µm @ 10 ma/cm 2 (triode test) *Contact us for information about cathodes with non-standard emission areas **Actual results depend strongly on the operating environment (10-8 Torr or better vacuum 16
level is strongly recommended for stable operation of the CNT cathodes) FIELD EMISSION PROPERTIES: Single emitter High current test Triode test Pulse mode (0.1% duty) Constant current mode (anode voltage is adjusted to maintain the constant emission current) 1.8 A/cm 2 achieved with excellent stability Electron transmission rate: ~60% 5. TRIODE CNT CATHODES CATALOG NUMBER: XRC-T01-SSR-R3 10 17
CHARACTERISTICS: Cathode type: Triode cathode Number of emitters: 1 Cathode substrate & Body: Mo / SS 304 Gate: W Gate to cathode gap: ~200 µm Emission area: 2 mm 10 mm (standard)* Emission current density**: 2 ma/cm 2 in DC mode Up to 2 A/cm 2 in pulse mode Electron transmission rate: ~70% Low threshold field: <3.5 V/µm @ 10 ma/cm 2 (triode test) *Contact us for information about cathodes with non-standard emission areas **Actual results depend strongly on the operating environment (10-8 Torr or better vacuum level is strongly recommended for stable operation of the CNT cathodes) 5. TRIODE CNT CATHODES CATALOG NUMBER: XRC-T01-SSC-R3 10 CHARACTERISTICS: Cathode type: Triode cathode Number of emitters: 1 Cathode substrate & Body: Mo / SS 304 18
Gate: W Gate to cathode gap: ~200 µm Emission area: 2 mm 10 mm (standard)* Emission current density: 2 ma/cm 2 in DC mode Up to 2 A/cm 2 in pulse mode Electron transmission rate: ~70% Low threshold field: <3.5 V/µm @ 10 ma/cm 2 (triode test) *Contact us for information about cathodes with non-standard emission areas **Actual results depend strongly on the operating environment (10-8 Torr or better vacuum level is strongly recommended for stable operation of the CNT cathodes) 5. TRIODE CNT CATHODES CATALOG NUMBER: XRC-T03-MO-R2 15 CHARACTERISTICS: Cathode type: Triode cathode Number of emitters: 3 (standard)* Cathode substrate & body: Mo / SS 304 Gate: W Gate to cathode gap: ~200 µm Emission area: 2 mm 15 mm or 1 mm 20 mm (standard)* Emission current density**: 2 ma/cm 2 in DC mode Up to 3.5 A/cm 2 in pulse mode Electron transmission rate: ~70% Low threshold field: <3.5 V/µm @ 10 ma/cm 2 (triode test) *Contact us for information about cathodes with customized number of emitters and emission areas **Actual results depend strongly on the operating environment (10-8 Torr or better vacuum level is strongly recommended for stable operation of the CNT cathodes) FIELD EMISSION PROPERTIES: 19
Single emitter High current test Triode test Pulse mode (0.1% duty) Constant current mode (anode voltage is adjusted to maintain the constant emission current) Initial aging is required to achieve good emission stability 3.5 A/cm 2 achieved with excellent stability Electron transmission rate: ~70% 8. CUSTOMIZED CNT CATHODES In addition to the standard CNT cathodes as described in the previous sections, XinRay also manufactures customized CNT cathodes according to customers specific requirements. Please contact XinRay for more information about the customized CNT cathodes! 9. PRICING AND LEAD TIME PRICING Call us for price information! *First time tooling fee may apply. **Minimum order of $1000 applies. ***Discount will be offered for order of 10 cathodes or more. Contact us for the discount rate! LEAD TIME Contact us for lead time information! 20
*Typical lead time is two weeks after receiving purchase & order when all the cathode components are in stock. **Extra time will be required for machining the cathode components if they are out of stock. 10. CONTACT INFORMATION P.O. Box 12848 7020 Kit Creek Road, Suite 210 Research Triangle Park, NC 27709 USA Tel: 1-919-313-9685 ext. 511 1-919-423-1832 Fax: 1-919-313-9686 Email: bgao@xinraysystems.com xinraysystems@xinraysystems.com 21