1.   Free-standing two-dimensional alumina grown by graphene-assisted Atomic Layer Deposition
E. Kheirandish1, N. Yavarishad1, D. Guan2, C. Yuan3, N. Kouklin1
1 Department of Electrical Engineering, Univ. of Wisconsin-Milwaukee, P.O. Box 413, Milwaukee, WI, USA
2 Department of Mechanical Engineering, Univ. of Wisconsin-Milwaukee, P.O. Box 413, Milwaukee, WI, USA
3 Department of Mechanical Engineering Case Western Reserve University, Cleveland, OH, USA

2. HRSEM, EDX, RAMAN and XRD of the 2D Alumina Flakes

3. Room Temperature Intensity Dependent PL and PLE
(Left) Room temperature intensity dependent photoluminescence and (right) room temperature PLE spectrum of the 2D alumina flakes. Inset shows the dependence of emission peak and output intensity of the detector with increase of the optical power.

4. I-V Characteristics and Hysteresis of 2D Alumina
I-V characteristics of a free- standing 2D Al2O3 flake network obtained at different temperatures; the upper left inset is enlarged I-V obtained at ~ 300K with arrows showing the direction of bias scans and the lower right inset is the plot of diff. conductance vs. temperature.

5. Conclusion
In this study we have successfully fabricated 2D Alumina on a 3D graphene scaffold using the ALD method. According to the elemental, electrical and optical analysis, as fabricated 2D alumina exhibits polycrystalline order and is luminescent at ~387 nm and exhibits a medium-strength defect-assisted light emission in the ultraviolet range. The I-V characteristic of the 2D alumina network is affected by the polarization current which could indicate higher dielectric constant in comparison to the bulk material. Temperature dependent transport measurements shows increase in the differential conductance of the 2D alumina network due to the thermal activation energy at ~350 K. This work could offer potential advantages for low-cost synthesis of device quality 2D nano-ceramic networks for applications in novel nano-electronics, MIM and MOS capacitors, random lasers, gas sensing and environmental cleaning.