Improvement of Al₂O₃ Films on Graphene Grown by Atomic Layer Deposition with Pre-H₂O Treatment

Abstract

We improve the surface of graphene by atomic layer deposition (ALD) without the assistance of a transition layer or surface functionalization. By controlling gas-solid physical adsorption between water molecules and graphene through the optimization of pre-H2O treatment and two-step temperature growth, we directly grew uniform and compact Al2O3 films onto graphene by ALD. Al2O3 films, deposited with 4-cycle pre-H2O treatment and 100-200 °C two-step growing process, presented a relative permittivity of 7.2 and a breakdown critical electrical field of 9 MV/cm. Moreover, the deposition of Al2O3 did not introduce any detective defects or disorders in graphene.

Reversible n-Type Doping of Graphene by H2O-Based Atomic-Layer Deposition and Its Doping Mechanism

“…19 In our previous work, we tried to deposit Al 2 O 3 films on graphene by ALD without the assistance of a transition layer or surface functionalization. 20 By controlling gas−solid physical adsorption between H 2 O molecules and graphene through the optimization of pre-H 2 O treatment and two-step temperature growth, we directly grew uniform and compact Al 2 O 3 films onto graphene by ALD. During the experimental process, we found that the doping type of graphene could be transformed, and interface charge-transfer doping might be the possible doping mechanism.…”

“…Both of these Raman spectroscopy results including the 2D peak left-shifting and blunting were consistent with those observed in typical n-type doping of graphene. 19,20,23 Notice that the 2D peak shifted up from 2685 to 2689 cm −1 , while the fwhm values of the 2D peak shifted down from 47 to 45 cm −1 after the n-type doped graphene was treated with RTA at 800°C…”

Transparent and Flexible Capacitors with an Ultrathin Structure by Using Graphene as Bottom Electrodes

“…However, these methods may damage the graphene, and inevitably introduce defects into the graphene. To overcome the drawbacks, Zheng et al [27] recently reported enhanced nucleation of Al 2 O 3 using adsorption of H 2 O on the graphene surface. In this way, a low leakage current was obtained by a two-step process at temperatures of 100 and 200 °C.…”

Effects of rapid thermal annealing on properties of HfAlO films directly deposited by ALD on graphene

“…Third, the chamber temperature was elevated to 200 1C to deposit another 6 nm thickness of HfAlO. Details about the optimization of preparation process can be found in our previous work [13,14]. After dielectrics growth, post-RTA at 800 1C for 30 s was implemented on HfAlO films.…”

“…Nevertheless, the carrier mobility of graphene is degraded significantly after functionalization. Our previous work tried to deposit high-κ dielectrics directly onto graphene by ALD with assistance of pre-H 2 O treatment [13,14]. The physically absorbed H 2 O on graphene could act as deposition sites and allow the subsequent dielectrics growth.…”