Fabrication and Evaluation of Organic Field-Effect Transistors (OFETs) : C₆₀MC₁₂

Fabrication and evaluation of spin-coated C₆₀MC₁₂ [C2415]-based OFETs

< Substrate >

• ODTMS-Si/SiO₂ (thickness of SiO₂：200 nm)

< Self-Assembly Monolayer (SAM) Treatment >

• Octadecyltrimethoxysilane (ODTMS) [O0256]
  1. Piranha etching (H₂SO₄:H₂O₂=4:1, 80 ºC, 2 h)
  2. Ultrasonication (Deionized water, Acetone, IPA, 10 min each)
  3. Exposure to vapor (IPA, 3 min)
  4. UV/O₃ treatment (1 h)
  5. Spin-coating of ODTMS solution (3 mM Trichloroethyrene, 3000 RPM, 60 sec)
  6. Exposure to ammonium vapor
     (The substrates were placed together in a desiccator with a vial of ammonium hydroxide for 16 h)
  7. Ultrasonication (Toluene, Acetone, IPA, 10 min each)

< Spin-Coating >

• Deposition rate of C₆₀MC₁₂ [C2415]: 012 mg/ml, Chloroform
• Spin-coating condition: 4000 RPM, 60 sec, N₂

< Vacuum Deposition >

• Deposition rate of Au: 0.2 Å/s (under a pressure of∼10⁻⁴ Pa)

< Post-Annealing Treatment >

• Annealing condition: 100 ºC, 18 h, vacuum

< Device Configuration >

• [n⁺-Si/SiO (200 nm) / C₆₀MC₁₂ [C2415] / Au (40 nm)]
• Top-Contact Bottom-Gate Type (TCBG)
• Channel Length: 50 μm
• Channel width: 1.5 mm

< Evaluation Condition >

• Characteristics of OFET devices were measured in a nitrogen glove box.
• Field-effect mobilities (μ) were determined from the transfer curves in the saturation regime using the following equation:
  I_D = (W/2L) μ Ci (V_G − V_th)²