Pulsed Laser Deposition of Indium Tin Oxide Thin Films on Nanopatterned Glass Substrates

Marcela Socol,Andreea Costas,Gabriel Socol,Florin Gherendi,Carmen Breazu,Oana Rasoga,Anca Stanculescu,Nicoleta Preda

doi:10.3390/coatings9010019

Abstract

Indium tin oxide (ITO) thin films were grown on nanopatterned glass substrates by the pulsed laser deposition (PLD) technique. The deposition was carried out at 1.2 J/cm2 laser fluence, low oxygen pressure (1.5 Pa) and on unheated substrate. Arrays of periodic pillars with widths of ~350 nm, heights of ~250 nm, and separation pitches of ~1100 nm were fabricated on glass substrates using UV nanoimprint lithography (UV-NIL), a simple, cost-effective, and high throughput technique used to fabricate nanopatterns on large areas. In order to emphasize the influence of the periodic patterns on the properties of the nanostructured ITO films, this transparent conductive oxide (TCO) was also grown on flat glass substrates. Therefore, the structural, compositional, morphological, optical, and electrical properties of both non-patterned and patterned ITO films were investigated in a comparative manner. The energy dispersive X-ray analysis (EDX) confirms that the ITO films preserve the In2O3:SnO2 weight ratio from the solid ITO target. The SEM and atomic force microscopy (AFM) images prove that the deposited ITO films retain the pattern of the glass substrates. The optical investigations reveal that patterned ITO films present a good optical transmittance. The electrical measurements show that both the non-patterned and patterned ITO films are characterized by a low electrical resistivity (<2.8 × 10−4). However, an improvement in the Hall mobility was achieved in the case of the nanopatterned ITO films, evidencing the potential applications of such nanopatterned TCO films obtained by PLD in photovoltaic and light emitting devices.

Highlights

Transparent conductive oxides (TCO) have been intensively studied in recent years due to their applications in many technological areas, such as optoelectronics devices, automobile and aircraft windows, and antireflection coatings [1,2,3,4]
The elemental composition of the TCO films grown by pulsed laser deposition (PLD) was evaluated by energy dispersive
The results are in agreement to those reported for indium tin oxide (ITO) films obtained by PLD [35], as the technique allows a stoichiometric transfer of the material from the target to the deposited film

Summary

Introduction

Transparent conductive oxides (TCO) have been intensively studied in recent years due to their applications in many technological areas, such as optoelectronics devices, automobile and aircraft windows, and antireflection coatings [1,2,3,4]. The NIL technique provides an ideal solution for patterning large areas with good resolutions at low cost and high throughput [29]. This special peculiarity of NIL opens the way for many economically feasible applications regarding the deposition of ITO films by different routes on patterning substrates obtained by NIL. Despite this aspect of NIL, few research papers have been published on this subject [30,31,32]. The information from this research can be helpful for developing potential applications of such patterned TCO films in organic optoelectronic devices

Experimental Section

Results and Discussions

Energy

Cross-sectional

Conclusions