Thin film transistors integrating CsPbBr3 quantum dots for optoelectronic memory application

All-inorganic perovskite cesium lead bromide (CsPbBr3) quantum dots (QDs) have been used as charge storage centers in floating-gate transistors. In this work, CsPbBr3 QDs are integrated into thin film transistors to create transistor-based memory. Unlike the floating-gate transistors previously reported, the CsPbBr3 QDs are placed between the dielectric and semiconductor layer, leading to direct contact with the semiconductor layer. Characterization of the device performance reveals that the CsPbBr3 QDs exhibit a strong tendency to store holes instead of electrons. Analysis unravels that this property possibly comes from the junction formed between the CsPbBr3 QDs and the transistor's semiconductor layer, which can facilitate hole injection from the semiconductor layer to the QDs under a negative gate bias, as well as the storage of the injected holes in the QDs. Devices using an organic semiconductor (P3HT) or two-dimensional material (graphene) consistently verify this speculation. Benefiting from the hole storage ability of the CsPbBr3 QDs, these devices show a benign non-volatile memory feature. As transistor-based memories, these devices can be programmed by electricity and erased by electricity or light illumination, rendering them as capable of optoelectronic memory application. This work offers an alternative approach for novel transistor-based optoelectronic memory.