Memory transistors based on two-dimensional (2D) ferroelectric semiconductors are intriguing for next-generation in-memory computing, which may surpass the prevailing Von Neumann architecture. To date several 2D FE materials have been unveiled, among which 2D In2Se3 is the most promising, as all the paraelectric (PE) (β), ferroelectric (FE) (α) and antiferroelectric (AFE) (β′) phases can be attained in the 2D quintuple layers. However, the large-scale synthesis of 2D In2Se3 film with desired phase is still in absence, and the stability conditions for each phase remain obscure.Here, we show the successful growth of centimetre (cm)-scale 2D β-In2Se3 film by chemical vapor deposition (CVD). We also obtain distinct cm-scale 2D β′-In2Se3 film by InSe precursor addition during CVD. More importantly, we demonstrate that asgrown 2D β′-In2Se3 film on mica substrates can be delaminated or transferred onto flexible or uneven substrates which simultaneously yields cm-scale 2D α-In2Se3 film through complete phase transition. Thus, a full spectrum of PE, FE and AFE 2D films are readily obtained by means of the correlated polymorphism in 2D In2Se3, enabling 2D memory transistors with high electron mobility (29 and 53 cm 2 V -1 s -1 in reverse sweep for β′-and α-In2Se3, respectively), and polarizable β′-α In2Se3 hetero-phase junctions with improved non-volatile memory performance. Our work pioneers in tailoring the 2D FE structures by precise phase engineering, and unlocks their great potentials for logic-in-memory electronics.

Hybrid perovskite single-crystalline thin films are promising for making high-performance perovskite optoelectronic devices due to their superior physical properties. However, it is still challenging to incorporate them into multilayer devices because of their on-substrate growth. Here, a wet transfer method is used in transferring perovskite single-crystalline films perfectly onto various target substrates. More importantly, large millimeter-scaled single-crystalline films can be obtained via a diffusion-facilitated space-confined growth method as thin as a few hundred nanometers, which are capable of sustaining excellent crystalline quality and morphology after the transferring process. The availability of these crystalline films offers us a convenient route to further investigate their intrinsic properties of hybrid perovskites. We also demonstrate that the wet transfer method can be used for scalable fabrication of perovskite single-crystalline film-based photodetectors exhibiting a remarkable photoresponsivity. It is expected that this transferring strategy would promise broad applications of perovskite single-crystalline films for more complex perovskite devices.

2D materials have drawn tremendous attention and extensive investigations for emerging applications in energy, electronics, and optoelectronics have been conducted. [1,2] In particular, 2D transition metal carbides and nitrides (MXenes) are considered as emerging energy materials. Enjoying their endowments in the high hydrophilic surface, porosity, and conductivity, MXenes possess widespread applications in battery, electrocatalyst, supercapacitor, and biochemistry. [3][4][5][6][7] MXenes are usually described by a chemical formula of M n+1 X n T x (n = 1, 2, and 3), where M represents an early transition metal (such as Ti, Nb, Cr, and V.), X stands for the C and/or N element, and T x is the

CVD grown 2D α-In layers own robust and intrinsic out-of-plane ferroelectricity maintained at high-temperature.