研究目的
To directly view the location and impact of shallow charge traps in an ultrathin organic transistor active layer and understand their spatial distribution and effects on carrier transport and noise.
研究成果
Shallow charge traps in ultrathin organic transistors are spatially uniformly distributed and cause rapid surface potential fluctuations due to trapping and release processes. This uniformity constrains the microscopic origin of shallow traps to small-scale structural defects and suggests that noise optimization in device applications requires controlling these dynamic trap landscapes.
研究不足
The study is conducted at room temperature in ambient air, which may not represent all operational environments. Measurements are far from contacts, potentially underestimating total trap density due to contact-induced traps. The ultrathin film approach may not generalize to thicker films or other materials.
1：Experimental Design and Method Selection:
The study uses Kelvin Probe Force Microscopy (KPFM) to spatially resolve surface potential fluctuations in the active channel of an ultrathin α-sexithiophene (α-6T) organic field-effect transistor (OFET) under varying gate biases. The design aims to correlate these fluctuations with charge trapping and release processes.
2：Sample Selection and Data Sources:
Ultrathin films of α-6T were grown on hexamethyldisilazane (HMDS)-treated SiO2 substrates with pre-patterned Au source and drain electrodes. Film thickness was calibrated to approximately 2.5 layers using atomic force microscopy.
3：5 layers using atomic force microscopy.
List of Experimental Equipment and Materials:
3. List of Experimental Equipment and Materials: Equipment includes an organic molecular beam deposition system for film growth, a Keithley 4200 semiconductor parameter analyzer for electrical measurements, a Janis CCR5 probe station, an Asylum MFP-3D atomic force microscope with KPFM capability, Budget Sensors ElectriMulti-75 conducting tips, and a Keithley 2400 Source-Measure Unit for gate bias application. Materials include α-6T, HMDS, SiO2 substrates, and Au electrodes.
4：Experimental Procedures and Operational Workflow:
Films were grown at 120°C, and transfer characteristics were measured immediately after growth. KPFM was performed in ambient air with source and drain grounded, and gate bias was swept slowly over about 12 hours. Topography and surface potential images were acquired as functions of gate bias.
5：Data Analysis Methods:
Surface potential data were analyzed to extract density of states (DOS) using a capacitor model. Power spectral density (PSD) of fluctuations was computed from KPFM images to characterize noise, with background subtraction below threshold voltage.
独家科研数据包，助您复现前沿成果，加速创新突破
获取完整内容
