Time-Dependent Field Effect in Three-Dimensional Lead-Halide Perovskite Semiconductor Thin Films.

Area of Science:

• Semiconductor physics
• Materials science

Background:

• Metal-halide perovskites are promising for optoelectronics and photovoltaics.
• Understanding charge transport (ionic and electronic) is crucial for device performance.
• Field effects in room-temperature, solution-processed perovskite transistors remain challenging to observe.

Purpose of the Study:

• Investigate time-dependent electrical characteristics of methylammonium lead iodide perovskite field-effect transistors (FETs).
• Analyze the impact of gate pulse duration on output current and apparent charge carrier mobility.
• Elucidate the mechanisms behind the observed dynamic field-effect behavior.

Main Methods:

• Fabrication of FETs using solution-processed, polycrystalline methylammonium lead iodide thin films.
• Time-resolved electrical measurements of FET output characteristics under varying gate pulse durations.
• Analysis of current variations to infer charge carrier mobility and transport limitations.

Main Results:

• Observed drastic variations in output current and apparent charge carrier mobility with applied gate pulse duration.
• Inferred ion accumulation at grain boundaries as the primary cause of carrier transport hindrance.
• Demonstrated the dynamic nature of the field effect in these perovskite FETs.

Conclusions:

• The field effect in solution-processed metal-halide perovskites is dynamic and influenced by ionic effects.
• Ion accumulation at grain boundaries significantly impacts charge transport across the FET channel.
• A novel investigation methodology is presented for characterizing charge transport in emerging perovskite semiconductors.