Fig. 2
From: ZnO composite nanolayer with mobility edge quantization for multi-value logic transistors
Quantized extended states of the zinc oxide (ZnO) composite nanolayer in the quantum well structure. a Top-view high-resolution transmission electron microscopy (HRTEM) image of the ZnO nanolayer. Dotted red circles correspond to ZnO nanocrystals embedded in ZnO amorphous domains. b Atomic structure of a ZnO nanolayer represented as a 2 × 2 periodic image of a 384-atom cell. Gray and red balls indicate Zn and O atoms, respectively. Blue hexagons show boundaries between nanocrystals in the inner region and amorphous domains at the outer region. c Total density of states for the ZnO composite nanolayer. Gray dashed lines with Ev and Ec represent the mobility edges of the valence band and conduction band, respectively. Quantized extended states just above Ec are denoted by a blue arrow. d Wavefunction (|Ψ|2) isosurface at the quantized extended state overlapped the atomic structure of the ZnO nanolayer. e Schematic of the structure of binary FETs with ZnO composite and polycrystalline nanolayers in a quantum well structure. f Cross-sectional transmission electron microscopy (TEM) image of a polycrystalline ZnO nanolayer with no amorphous domains. g Linear-scale transfer characteristics of two binary transistors with a ZnO composite nanolayer (red) or highly crystalline ZnO nanolayer (black). h A schematic energy band diagram of the ZnO composite nanolayer FET at VG > 1 V
