FOR FUTURE NANO-ELECTRONIC TECHNOLOGIES including displays, light weight, transparent and flexible characteristics are required for numerous applications such as heads-up displays and conformal integrations. Advances in materials and processing strategies, thin-film transistors (TFTs) built on one-dimensional (1-D) semiconductor nanomaterials and high-k dielectrics (including organic and inorganic materials), offer unique attractions for use in next-generation nano-electronic applications. TFTs made of 1-D nanostructured materials have the advantages of low operating voltage (low power consumption), high device mobility (500-4,000 cm2/V·sec) in comparisons of organic or poly/amorphous Si TFTs (mobility: 1 cm2/V·sec for organic and amorphous TFTs), light weight, potential transparency, and mechanical flexibility. However, there are several challenges to overcome before such nano-electronic products are a reality.
We have pioneered the synthesis of different nanowires through a laser ablation method, including In2O3, SnO2 and YBCO, LCMO, LSMO, and Fe3O4 nanowires. Our capability of obtaining high-quality single crystalline nanowires enables us to explore the nanowire device physics and further applications. Our most recent achievement is the demonstration of controlling an active-matrix organic light-emitted diode (AMOLED) display by transparent Arsenic-doped In2O3 nanowire TFTs. The use of As-doped In2O3 nanowire is not only employed for the first time in the of transparent TFTs (TTFTs), but also improves the device performance (mobility: 1488.8 cm2/Vs, on/off ratio: > 106, subthreshold slope: 80 mV/dec), in comparisons of undoped In2O3 and other metal oxide nanowire TTFTs.
A fully integrated seven-segment AMOLED display was fabricated with good transparency of 40 % and each pixel was controlled by two nanowire transistors. This display successfully showed different digital numbers. Our results suggest that As-doped In2O3 nanowires can be valid building blocks for future transparent electronics and display electronics.
Furthermore, via the cooperation with Purdue University and Northwestern University, we have demonstrated fully transparent and flexible TFTs on glass and plastic substrate using In2O3 and ZnO nanowires as active channels. The as-fabricated nanowire TFTs exhibit high-performance n-type transistor characteristics with an optical transparency of ~ 82%. In comparisons of bulk or thin-film transistors made from amorphous silicon (a-Si) and some orgainic materials, the mobility of nanowire TTFTs are about several hundred times higher than those devices. In addition, nanostructured material based TTFTs have an extra advantage of low temperature process, which show high compatibility with different device substrates. We believe this work will pave the way for nanomaterials to transparent and flexible electronics
We report the first demonstration of AMOLED displays driven exclusively by nanowire electronics and the display exhibits 300 cd/m2 brightness with relatively low processing temperatures, which is suitable for integration on plastic substrates.
1. “Fabrication of fully transparent nanowire transistors for transparent and flexible electronics.”
S. Ju, A. Facchetti, Y. Xuan, J. Liu, F. Ishikawa, P. D. Ye, C. Zhou, T. J. Marks, and D. B. Janes,
Nature Nanotechnology 2, 378 (2007). (PDF)
2. “Transparent Active Matrix Organic Light-Emitting Diode Displays Driven by Nanowire Transistor Circuitry”
S. Ju, J. Li, J. Liu, P. Chen, Y. Ha, F. Ishikawa, H. Chang , C. Zhou, A. Facchetti, D. B. Janes and T. J. Marks,
Nano Letters, 8, 997 (2008). (PDF)
3. “Chemical sensors and electronic noses based on 1-D metal oxide nanostructures”
P. C. Chen, G. Z. Shen, and C. Zhou,
IEEE Transactions on Nanotechnology 7, 668 (2008). (PDF)
4. “Diameter-controlled growth of single-crystalline In2O3 nanowires and their electronic properties.”
C. Li, D. Zhang, S. Han, X. Liu, T. Tang, and C. Zhou,
Advanced Materials 15, 143 (2003). (PDF)
5. “Electronic transport studies of single-crystalline In2O3 nanowires”
D. Zhang, C. Li, S. Han, X. L. Liu, T. Tang, W. Jin, and C. Zhou
Applied Physics Letters 82, 112 (2003). (PDF)
6. "Laser Ablation Synthesis and Electronic Transport Studies of Tin Oxide Nanowires"
Z. Liu, D. Zhang, S. Han, C. Li, T. Tang, W. Jin, X. Liu, B. Lei, and C. Zhou,
Advanced Materials 15, 1754 (2003). (PDF)
7.“Tuning Electronic Properties of In2O3 Nanowires by Doping Control”
B. Lei, C. Li, D. Zhang, T. Tang and C. Zhou,
Applied Physics A 79, 439 (2004). (PDF)
8.“One-dimensional Transport of In2O3 Nanowires”
F. Liu, M. Bao, K. L. Wang, C. Li, B. Lei, and C. Zhou,
Appl. Phys. Lett. 86, 213101 (2005). (PDF)
9.“1/f SnO2 nanowire transistors”,
S. Ju, P. Chen, C. Zhou, Y. Ha, A. Facchetti, T. J.Marks, S. Kim, S. Mohammadi, and D. B. Janes,
Applied Physics Letters, 92, 243120 (2008). (PDF)
10. “High performance In2O3 nanowire transistors using organic gate nanodielectrics”
S. Ju, F. N. Ishikawa, P. C. Chen, H. K. Chang, C. Zhou, Y. G. Ha, J. Liu, A. Faccheti, T. J. Marks, and D. B. Janes,
Applied Physics Letters 92, 222105 (2008). (PDF)