Perovskite Flash Memory with a Single-Layer Nanofloating Gate

Abstract

Here we use triple-cation metal–organic halide perovskite single crystals for the transistor channel of a flash memory device. Moreover, we design and demonstrate a 10 nm thick single-layer nanofloating gate. It consists of a ternary blend of two organic semiconductors, a p-type polyfluorene and an n-type fullerene that form a donor:acceptor interpenetrating network that serves as the charge storage unit, and of an insulating polystyrene that acts as the tunneling dielectric. Under such a framework, we realize the first non-volatile flash memory transistor based on a perovskite channel. This simplified, solution-processed perovskite flash memory displays unique performance metrics such as a large memory window of 30 V, an on/off ratio of 9 × 107, short write/erase times of 50 ms, and a satisfactory retention time exceeding 106 s. The realization of the first flash memory transistor using a single-crystal perovskite channel could be a valuable direction for perovskite electronics research.

Switched‐On: Progress, Challenges, and Opportunities in Metal Halide Perovskite Transistors

“…[52] Vasilopoulou et al used higher amounts of Rb + salts and reported only p-type operation for Rb 0.15 (MAFA) 0.85 PbI 3 . [153] In 2019, the first transistor based on a low-bandgap mixed lead-tin perovskite layer, that is, FAPb 0.5 Sn 0.5 I 3 was demonstrated (Figure 7c). [111] This device operated at room temperature upon p-type doping with ZnI 2 and yielded a mobility of μ h = 0.007 cm 2 V -1 s -1 and enhanced stability resulting from the reduction in tin-rich clusters.…”

“…Gate voltage dependent tunneling of holes from the perovskite into the fullerene:polyfluorene organic blend through the insulating polystyrene component enabled memory transistor operation with a wide operating voltage window and memory on/off ratios as high as 10 7 . The devices exhibited good retention of their programmed state for up to 10 6 s. [153] Gedda et al investigated a blend of (PEA) 2 PbBr 4 :[2,7-dioctyl [1]benzothieno [3,2-b] benzothiophene] (C 8 -BTBT) for memory application. In this 2D Ruddlesden-Popper perovskite, the lead bromide layers separated by the insulating organic cations acted as floating gate and allowed effective trapping/de-trapping of holes depending on the applied gate voltage.…”

“…used higher amounts of Rb + salts and reported only p‐type operation for Rb 0.15 (MAFA) 0.85 PbI 3 . [ 153 ]…”

Recent advances in metal nanoparticle‐based floating gate memory

“…Thanks to the development of cutting‐edge material, optimized memory device structures based on different materials can be fabricated. [ 30,103 ] To simplify the separate deposition process of dielectric layer and floating gate layer, Yan et al. reported a nano‐floating gate memory using ZnSe@ZnS core–shell quantum dots which plays dual roles as discrete charge storage and tunneling centers.…”

Halide perovskite for low‐power consumption neuromorphic devices

“…(G) Plot of write and erase current densities versus time for the evaluation of flash memory retention time. (D)–(G) Reproduced with permission: Copyright 2020, American Chemical Society 73 …”