High-Performance Nanofloating Gate Memory Based on Lead Halide Perovskite Nanocrystals

Abstract

Lead halide perovskites have been extensively investigated in a host of optoelectronic devices, such as solar cells, light-emitting diodes, and photodetectors. The halogen vacancy defects arising from the halogen-poor growth environment are normally regarded as an unfavorable factor to restrict the device performance. Here, for the first time, we demonstrate the utilization of the vacancy defects in lead halide perovskite nanostructures for achieving high-performance nanofloating gate memories (NFGMs). CH 3 NH 3 PbBr 3 nanocrystals (NCs) were uniformly decorated on the CdS nanoribbon (NR) surface via a facile dip-coating process, forming a CdS NR/CH 3 NH 3 PbBr 3 NC core−shell structure. Significantly, owing to the existence of sufficient carrier trapping states in CH 3 NH 3 PbBr 3 NCs, the hybrid device possessed an ultralarge memory window up to 77.4 V, a long retention time of 12 000 s, a high current ON/OFF ratio of 7 × 10 7 , and a longterm air stability for 50 days. The memory window of the device is among the highest for the low-dimensional nanostructurebased NFGMs. Also, this strategy shows good universality and can be extended to other perovskite nanostructures for the construction of high-performance NFGMs. This work paves the way toward the fabrication of new-generation, high-capacity nonvolatile memories using lead halide perovskite nanostructures. KEYWORDS: nanofloating gate memories (NFGMs), perovskite nanocrystals, CH 3 NH 3 PbBr 3 , CdS nanoribbons (NRs), large memory window

Improving Performance of Nonvolatile Perovskite‐Based Photomemory by Size Restrain of Perovskites Nanocrystals in the Hybrid Floating Gate

“…nanocrystals (NCs) to fabricate a perovskite-based nano-floating gate and employed it to develop a transistor-type memory. [26] Although the developed FET is an electric-program device, [27] the embedment of perovskite NCs into the floating gate might enrich the photo-responsivity of the derived FETs, enabling the possibility of photo-programing. [27,28] This can be evidenced by the successful applications of perovskite hybrids in the photodetectors.…”

“…used MAPbBr 3 nanocrystals (NCs) to fabricate a perovskite‐based nano‐floating gate and employed it to develop a transistor‐type memory. [ 26 ]…”

Recent Process of Flexible Transistor‐Structured Memory

“…The FGTM based on NRs provides a viable solution, due to a facile dip‐coating process ( Figure a). [ 84 ] The CdS NR surface was uniformly decorated by CH 3 NH 3 PbBr 3 nanocrystals (NCs) to form a CdS NR/CH 3 NH 3 PbBr 3 NC core–shell structure (Figure 5b,c). Energy band diagrams of the FGTM device during the charge storage process could elaborate the working mechanism (Figure 5d).…”

“…However, more than two orthogonal solvents are commonly required in solution processes. [84,85] That means the uses of the two types of nanostructures are impeded by the complexity of preparing them in solution. Use of 2D material flakes could simplify the fabrication procedure.…”

“…The inset shows transfer characteristic curves of the memory device exposed to air for 0 and 50 d. Reproduced with permission. [84] Copyright 2019, American Chemical Society. On-current, off-current, and on/off ratio of FGTM along with applied strain.…”