META 2014 CONFERENCE, 20 – 23 MAY 2014, SINGAPORE Distinction of Opto-Electronic Properties between Random and Ordered Nano-Holed Layers Mikita Marus 1 , Aliaksandr Hubarevich 1 , Wang Hong 1 , Eugeny Muha 2 , Aliaksandr Smirnov 2 , Sun Xiaowei 1* and Fan Weijun 1* 1 School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 2 Department of Micro- and Nano-Electronics, Belarusian State University of Informatics and Radioelectronics, Minsk, Belarus *corresponding author, E-mail: EXWSun@ntu.edu.sg; EWJFan@ntu.edu.sg Abstract The distinction of opto-electrical properties in case of alu- minum, gold and silver random and ordered nano-holed layers was demonstrated. It is found that transmittance is dropped due to the shortening of plasmon polaritons propa- gating length within the Anderson localization effect, while sheet resistance increases in regard of decrement of metal connections volume. Eventually gold and silver possess the transmittance of more than 80% and the sheet resis- tance of 20 Ohm/sq regardless of holes arrangement. Al- iminum demonstrates comparable parameters only with or- dered patterns. 1. Introduction The future extinction of indium [1] which is main com- ponent of the indium-tin-oxide (ITO) leads the scientists to create alternative transparent conductive layers (TCLs) [2–8]. The novel TCLs must have transmittance and sheet resistance around 80% and 20 Ohm/sq, respectively [1], as well as large deposition area ranging from micrometers to tens of centimeters; moreover the formation method should be a cheap one. The simplest TCLs are planar gold (Au) films of thick- ness less than 50 nm. The transmittance of 10 nm Au thick films is around 60% in visible wavelength spectrum and sheet resistance is 15 Ohm/sq [2]. The further patterning of films leads to optical properties improvement, while the sheet resistance unfortunately grows. Therefore the type and dimensions of the patterning are crucial for optimiz- ing the opto-electronic properties. This trade-off has cur- rently been investigated in Refs. [8, 9]. However the pri- mary research focus was concentrated on the uniform pat- terns while little attention has been paid to the random ones. This paper presents the detailed theoretical study of ran- dom nano-holed metallic layers and their comparative anal- ysis with uniform structures. Calculations show that opto- electronic parameters of metals with stronger plasmon res- onance are less affected by disordering effect. 2. Methodology The holed metallic layers of aluminum (Al), Au and silver (Ag) on glass substrates with size of 2x2 μm were used in simulations. Cylindrical shape holes were aligned parallel to Z axis. Holes locations were distributed according to p+dp, where p is each hole initial position in the hexagonal arrangement and dp is its deviation along XY plane. Each holes radius was obtained by adding of deviated value to initial radius: r+dr. The normal and uniform distributions were used to get dp and dr. Furthermore, the normal one had a broader range of dp and dr. The optical properties were simulated using the finite- difference time-domain method (FTDT) which is commer- cially available within Lumerical software [10]. The inci- dent light distributed along Z axis. The periodic boundary conditions and perfectly matched layers were applied par- allel and perpendicular to Z axis correspondingly. The sheet resistance was calculated by using the per- colation theory model [11]. According to this theory the following equation is used: R s = 1 hσ 0 (φ f - φ crit ) t , (1) where R s , h, σ 0 , φ f , φ crit and t are sheet resistance, layer thickness, unpatterned solid layer conductivity, patterned metal volume fraction, critical patterned metal volume frac- tion when conductivity is tending to zero and critical expo- Figure 1: Nano-holed layers simulation concept. Layer types: (a) constant interhole distance and holes radius; (b, c) constant interhole distance and random holes radius, ob- tained by uniform and normal distributions, accordingly; (d) random interhole distance and constant holes radius; (e, f) random interhole distance and holes radius, obtained by uniform and normal distributions, accordingly.