Significant Joule self-heating pervasive in the emergent thin-film transistor studies†

In this Perspective, recent literature on field-effect transistors based on emergent semiconducting materials, including metal-halide perovskites, conjugated polymers, and small-molecule organic semiconductors, is analyzed in terms of electric power and power density reached in transistors’ channel during their measurements. We used an in situ IR imaging to directly obtain the surface temperature distribution of biased devices under the experimental conditions commonly used in the literature. It is shown that at such conditions, the semiconducting channel would be resistively self-heated to significant temperatures, easily in excess of 150 °C. This implies a non-equilibrium device operation, possible materials’ degradation, parameter drift, and, in the best-case scenario, a non-room-temperature mobility extracted from such measurements. We show that this problem is rather common in various subfields represented in the literature, indicating that paying attention to the biasing conditions in transistor research and monitoring the local temperature of the semiconducting channel are necessary.