Goal: The goal of this course is to understand the preparation, physics, and application of thin-film silicon for flexible electronics. The course will start with an overview on the flexible electronics, followed by the growth and properties of the individual silicon layers. The physics, structure, fabrication, and properties of some thin-film silicon based devices, such as thin-film transistors and photodiodes, will be studied as well. In the end, the current fabrication technology and challenges for flexible electronics will be discussed.
Course Outline:
1. Introduction to flexible electronics
1.1 Structure of large area electronics (overview)
1.2 Flexible substrates: glass, metal foil, plastic
1.3 Backplane materials: silicon, organics, ITO, conductive polymer
1.4 Frontplane: display (organic light emitting diode, liquid crystal, E-Ink), sensor, actuator
1.5 Encapsulation
2. Silicon material
2.1 Range of structures of silicon:
amorphous, nanocrystalline,microcrystalline, polycrystalline, single-crystal
2.2 Growth techniques (overview):
direct deposition, transfer technology
2.3 Vacuum techniques for growing silicon thin films:
thermal evaporation/MBE, sputtering, plasma enhance chemical vapor
deposition, catalytic decomposition
2.4 Polysilicon crystallized from precursor films:
furnace, catalyzed, laser-crystallization (LTPS)
3. Electronic properties
3.1 Single crystal:
band structure, transport, optical, doping
3.2 Poly-, micro-, nano-crystalline silicon:
effects of grain boundaries, optical absorption spectra
3.3 Amorphous silicon:
band structure, optical absorption spectra, carrier transport, doping,
dangling-bond defects, metastability in amorphous silicon
4. Devices
4.1 Thin-film transistors (TFTs):
4.1.1 amorphous silicon: review of MOSFET, physics, device structure,
fabrication procedure, stability
4.1.2 nanocrystalline silicon
4.1.3 polycrystalline silicon
4.2 Amorphous silicon photodiode:
physics of p-i-n diodes, structure and fabrication, characteristics
4.3 Thin-film solar cells
4.4 Other applications
5. Fabrication of flexible electronics
sheet, roll-to-roll web, printing, shaping