Bi-exponential decay model of electron in Al2O3/Au NCs/Al2O3 structure

As state-of-the-art electronic chips were miniaturized to its limit, many small dimension issues, such as crosstalk noise, parasite capacitance, and tunneling of charges, emerged. Studying such issues shall be of interest to the research and industry field. Here, we studied the electrical behavior of electrons injected in an array of nanostructures embedded on Al2O3 dielectrics. Our multi-stack device comprised Au nanoclusters, tunneling and blocking Al2O3 oxide layers, and a Si substrate. The electrons were injected by applying a bias at the top of the atomic force microscopy tip in contact while grounding the Si substrate. Its retention and diffusion behaviors were observed by measuring the contact potential difference (CPD). The measured CPD data with time were well fitted to the bi-exponential function, which had two time constants tau(1) and tau(2). It indicated that at least two dominant tunneling mechanisms existed, so it was confirmed with I-V measurement using a simple tunneling device (Pt/Al2O3/Si structure). This work may provide a tool for analysis of charge transportation in a miniaturized nanostructure.