Direct Laser Writing of Nanodiamond Films from Graphite under Ambient Conditions

Abstract

Synthesis of diamond, a multi-functional material, has been a challenge due to very high activation energy for transforming graphite to diamond, and therefore, has been hindering it from being potentially exploited for novel applications. In this study, we explore a new approach, namely confined pulse laser deposition (CPLD), in which nanosecond laser ablation of graphite within a confinement layer simultaneously activates plasma and effectively confine it to create a favorable condition for nanodiamond formation from graphite. It is noteworthy that due to the local high dense confined plasma created by transparent confinement layer, nanodiamond has been formed at laser intensity as low as 3.7 GW/cm2, which corresponds to pressure of 4.4 GPa, much lower than the pressure needed to transform graphite to diamond traditionally. By manipulating the laser conditions, semi-transparent carbon films with good conductivity (several kΩ/Sq) were also obtained by this method. This technique provides a new channel, from confined plasma to solid, to deposit materials that normally need high temperature and high pressure. This technique has several important advantages to allow scalable processing, such as high speed, direct writing without catalyst, selective and flexible processing, low cost without expensive pico/femtosecond laser systems, high temperature/vacuum chambers.

Photothermal effects during nanodiamond synthesis from a carbon aerogel in a laser-heated diamond anvil cell

“…Heating and rastering at 22 MW/cm 2 produced a diamond line width of 4.0 ± 0.6 µm. To the best of the author's knowledge, this is the highest resolution of diamond film patterning to date [43].…”

Spatially resolved nanostructural transformation in graphite under femtosecond laser irradiation

“…Here, the high temperature and the pressure are produced by the photon absorption and respectively the expanding ablation plume. Laser pulse is usually having hundreds of mJ/pulse energy [7,8].…”

“…Another proposed technique for the graphite to diamond conversion is detonation [6], where the process is still based on the high temperature and high-pressure, that are produced by a blast. Laser irradiation came later among the considered techniques for diamond fabrication, with the advantages of a more precise localization of the diamond fabrication place on the target [7] and less demanding experimental conditions. Here, the high temperature and the pressure are produced by the photon absorption and respectively the expanding ablation plume.…”

“…Here, the high temperature and the pressure are produced by the photon absorption and respectively the expanding ablation plume. Laser pulse is usually having hundreds of mJ/pulse energy [7,8].Short pulse lasers (20 -100 fs) were later used to process the diamond or diamond-like surfaces [9][10][11] or even for diamond graphitization [12][13][14]. However, because of the short duration of the laser-matter interaction and low heating effect during the ablation processes [15] theoretical studies have considered femtosecond laser beams as unlikely to produce a graphite to diamond transformation.…”

Laser-induced versus shock wave induced transformation of highly ordered pyrolytic graphite

“…More recently, Nian et al synthesized nano-diamonds from graphite through direct low intensity laser irradiation using a transparent confinement layer to generate a local high dense plasma. The pressure was estimated to be 4.4 GPa [11].…”