High performance diamond-like carbon layers obtained by pulsed laser deposition for conductive electrode applications

Abstract

For the future, one of the biggest challenge faced to the technologies of flat panel display and various optoelectronic and photovoltaic devices is to find an alternative to the use of transparent conducting oxides like ITO. In this new approach, the objective is to grow high conductive thin-layer graphene (TLG) on the top of diamond-like carbon (DLC) layers presenting high performance. DLC prepared by pulsed laser deposition (PLD) have attracted special interest due to a unique combination of their properties, close to those of monocrystalline diamond, like its transparency, hardness and chemical inertia, very low roughness, hydrogen-free and thus high thermal stability up to 1000 K. In our future work, we plane to explore the synthesis of conductive TLG on top of insulating DLC thin films. The feasibility and obtained performances of the multi-layered structure will be explored in great details in the short future to develop an alternative to ITO with comparable performance (conductivity of transparency). To select the best DLC candidate for this purpose, we focus this work on the physicochemical properties of the DLC thin films deposited by PLD from a pure graphite target at two wavelengths (193 and 248 nm) at various laser fluences. A surface graphenization process, as well as the required efficiency of the complete structure (TLG/DLC) will clearly be related to the DLC properties, especially to the initial sp 3 /sp 2 hybridization ratio. Thus, an exhaustive description of the physicochemical properties of the DLC layers is a fundamental step in the research of comparable performance to ITO.

Kinetics of graphitization of thin diamond-like carbon (DLC) films catalyzed by transition metal

“…A KrF laser source (248 nm wavelength, 30 ns pulse frequency) was used with a nuclear-grade graphite target (purity 5N) at a substrate-target distance of 5 cm. The laser fluence was within the range 4-6 J/cm 2 , which corresponds to approximately 210 8 W/cm 2 , a power density for which we found a maximum of sp 3 carbon formation [20]. The deposited ta-C film thickness was around 15 nm.…”

“…The deposited ta-C film thickness was around 15 nm. Further experimental details on the preparation, the determination of the sp 3 /sp 2 ratio and the carbon density of the films are reported in references [20,21]. Samples studied here have a density of about 3 g/cm 3 and 70% of sp 3 content.…”

UV laser annealing of Diamond-Like Carbon layers obtained by Pulsed Laser Deposition for optical and photovoltaic applications

“…After optimal focusing and taking in account all optical component energy losses, we reach ontarget fluences tuneable from 2 up to 15 J/cm 2 . As shown in previous studies [15,18,19], DLC thin films are deposited at room temperature to obtain the highest adamant character. The layers were mainly deposited on oxidized silicon (SiO 2 (63 nm)/Si substrates of 1 × 1 cm 2 ).…”

“…As we previously demonstrated, the sp 2 and sp 3 amount ratio is highly depending on the laser wavelength and the energy density used to ablate the carbon. Those parameters condition the optical and electrical DLC properties [15].…”

Effect of sputtering pressure on the surface topography, structure, wettability and tribological performance of DLC films coated on rubber by magnetron sputtering

“…DLC thin films have been prepared by various methods including pulsed laser deposition [8], ion beam sputtering [9], plasma enhanced chemical vapour deposition (PECVD) [10] and magnetron sputtering (MS) [11]. In this field, Lubwama et al [12][13][14][15] used a combination of closed field unbalanced magnetron sputtering ion plating and PECVD with an Ar/C 4 H 10 plasma to deposit DLC and Si-DLC films with and without Si-C interlayer onto nitrile rubber at a low substrate bias of −30 V and investigated the triboperformance of DLC and Si-DLC films.…”