TY - JOUR
T1 - Driving characteristics of the electrowetting-on-dielectric device using atomic-layer-deposited aluminum oxide as the dielectric
AU - Chang, Jong Hyeon
AU - Choi, Dae Young
AU - Han, Seungoh
AU - Pak, James Jungho
N1 - Funding Information:
Acknowledgments The authors thank NCD Technology in Korea for Al2O3 ALD service. This work was supported by the National Research Foundation of Korea (NRF) through a grant provided by Ministry of Education, Science and Technology (MEST) in 2009 (No. K20601000002–09E0100–00200) and also supported by a Korea University Grant.
PY - 2010/2
Y1 - 2010/2
N2 - Electrowetting on dielectric (EWOD) is useful in manipulating droplets for digital (droplet-based) microfluidics, but its high driving voltage over several tens of volts has been a barrier to overcome. This article presents the characteristics of EWOD device with aluminum oxide (Al2O3, ε r ≈ 10) deposited by atomic layer deposition (ALD), for the first time as the high-k dielectric for lowering the EWOD driving voltage substantially. The EWOD device of the single-plate configuration was fabricated by several steps for the control electrode array of 1 mm × 1 mm squares with 50 μm space, the dielectric layer of 1,270 Å thick ALD Al 2O3, the reference electrode of 20 μm wide line electrode, and the hydrophobic surface treatment by Teflon-AF coating, respectively. We observed the movement of a 2 μl water droplet in an air environment, applying a voltage between one of the control electrodes and the reference electrode in contact with the droplet. The droplet velocity exponentially depending on the applied voltage below 15 V was obtained. The measured threshold voltage to move the droplet was as low as 3 V which is the lowest voltage reported so far in the EWOD researches. This result opens a possibility of manipulating droplets, without any surfactant or oil treatment, at only a few volts by EWOD using ALD Al2O3 as the dielectric.
AB - Electrowetting on dielectric (EWOD) is useful in manipulating droplets for digital (droplet-based) microfluidics, but its high driving voltage over several tens of volts has been a barrier to overcome. This article presents the characteristics of EWOD device with aluminum oxide (Al2O3, ε r ≈ 10) deposited by atomic layer deposition (ALD), for the first time as the high-k dielectric for lowering the EWOD driving voltage substantially. The EWOD device of the single-plate configuration was fabricated by several steps for the control electrode array of 1 mm × 1 mm squares with 50 μm space, the dielectric layer of 1,270 Å thick ALD Al 2O3, the reference electrode of 20 μm wide line electrode, and the hydrophobic surface treatment by Teflon-AF coating, respectively. We observed the movement of a 2 μl water droplet in an air environment, applying a voltage between one of the control electrodes and the reference electrode in contact with the droplet. The droplet velocity exponentially depending on the applied voltage below 15 V was obtained. The measured threshold voltage to move the droplet was as low as 3 V which is the lowest voltage reported so far in the EWOD researches. This result opens a possibility of manipulating droplets, without any surfactant or oil treatment, at only a few volts by EWOD using ALD Al2O3 as the dielectric.
KW - Aluminum oxide (AlO)
KW - Atomic layer deposition (ALD)
KW - Digital microfluidics
KW - Electrowetting on dielectric (EWOD)
KW - Single-plate configuration
UR - http://www.scopus.com/inward/record.url?scp=77649238688&partnerID=8YFLogxK
U2 - 10.1007/s10404-009-0511-9
DO - 10.1007/s10404-009-0511-9
M3 - Article
AN - SCOPUS:77649238688
VL - 8
SP - 269
EP - 273
JO - Microfluidics and Nanofluidics
JF - Microfluidics and Nanofluidics
SN - 1613-4982
IS - 2
ER -