# Characterization of Graphene Carbon Produced by Pulsed Laser Ablation of Sacrificial Carbon Tapes
## 1 Introduction  
Amorphous and crystalline sp\({}^{2}\) carbon has attracted great interest in the fields of materials science and engineering, because of its unique physical, chemical and mechanical properties [1, 2, 3]. Graphenic quantum confined structures, such as graphene quantum dots (GQDs) and graphene oxide quantum dots (GOQDs), have shown promising applications in the fields of catalysis, optoelectronics, energy storage, and bio-imaging [4, 5, 6, 7]. The attractive photoluminescence properties of GQDs place them amongst the new optical materials for advanced applications, such as light-emitting devices, optical sensing, and bio-imaging. GQDs exhibit a high quantum yield with excellent photostability, owing to the intrinsic band structure and physicochemical robustness, which is beneficial for optoelectronic applications [6]. Recently, much attention has been focused on the use of amorphous carbon for fast switching devices [8, 9] and nonvolatile memory (NVM) applications [10, 11]. Different switching mechanisms, from sp\({}^{2}\)-dominated graphite-like amorphous carbon with low resistivity to the sp\({}^{3}\)-dominated diamond-like form with high resistivity, have been reported [12]. It was shown that changing the sp\({}^{2}\)/sp\({}^{3}\) ratio can significantly influence the conduction behavior of carbon films [10]. Carbon-based layered and two-dimensional materials, including turbostratic carbon and multilayer graphene, are of great interest because of their high potential for electrochemical and biosensing applications [13]. These materials exhibit a large surface area,which can be further modified by the generation of pores and the incorporation of dopants. Graphene-rich amorphous films also have prospective applications in surface modification, due to their chemical inertness, and excellent friction and wear performance [1; 14], as well as their low internal stress and high conductivity. In contrast to pristine graphite and graphene, graphene-like carbon (GLC) and related materials, including reduced graphene oxide, contain lattice defects and residual oxygen-containing functional groups, which are beneficial for their capacitance and electron transfer kinetics. The reduction of graphene oxide (GO) has recently been considered as one of the promising methods for the large-scale production of graphene [15; 16; 17]. The main advantages of GO and related materials are: their excellent water dispersibility, inexpensive production, and tunability of physical and chemical properties by controlling the number of functional groups. Reduced graphene oxide is a conductive material of high potential importance in electronic applications, including optoelectronics [18], composite materials, sensors, and wearable technology [19]. Other promising applications of rGO include energy storage devices and nonvolatile resistive random access memory (RRAM) devices. Reduced graphene oxide and so-called graphene-like graphite (GLG) have been successfully used to create electrodes for supercapacitors and Li-ion batteries [13; 16; 20]. Additionally, rGO has been successfully applied in ITO/rGO/ITO transparent and flexible RRAM cells [21], with multilevel switching properties and relatively high endurance. The common methods of GO reduction involve using electron beams, laser irradiation, heat, and chemical reduction. Recently, laser irradiation has been proposed as a promising tool for the reduction of GO [16; 18; 19; 22]. The laser reduction of GO is based on the photochemical removal of oxygen functional groups from the GO surface, which is accompanied by laser ablation and molecular restructuring of the carbon lattice into the sp\({}^{2}\)-conjugated graphene structure [22]. Laser reduction has many advantages over these methods. In addition to the spatial control and energy efficiency, the laser reduction process is much cleaner and less toxic than any chemical method, as it does not require chemical reactions in strong acids, or long-term washing procedures [16; 19].