title: 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/cm(2), 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.
authors.affiliation: School of Industrial Engineering, Purdue University, West Lafayette, IN, USA.
authors.forename: Qiong
authors.initials: Q
authors.lastname: Nian
authors.affiliation: School of Materials Engineering, Purdue University, West Lafayette, IN, USA.
authors.forename: Yuefeng
authors.initials: Y
authors.lastname: Wang
authors.affiliation: School of Industrial Engineering, Purdue University, West Lafayette, IN, USA.
authors.forename: Yingling
authors.initials: Y
authors.lastname: Yang
authors.affiliation: School of Industrial Engineering, Purdue University, West Lafayette, IN, USA.
authors.forename: Ji
authors.initials: J
authors.lastname: Li
authors.affiliation: School of Industrial Engineering, Purdue University, West Lafayette, IN, USA.
authors.forename: Martin Y
authors.initials: MY
authors.lastname: Zhang
authors.affiliation: Department of Physics, Purdue University, West Lafayette, IN, USA.
authors.forename: Jiayi
authors.initials: J
authors.lastname: Shao
authors.affiliation: Department of Physics, Purdue University, West Lafayette, IN, USA.
authors.forename: Liang
authors.initials: L
authors.lastname: Tang
authors.affiliation: 1] School of Industrial Engineering, Purdue University, West Lafayette, IN, USA [2] School of Mechanical Engineering, Purdue University, West Lafayette, IN, USA [3] Birck nanotechnology Center, Purdue University, West Lafayette, IN, USA.
authors.forename: Gary J
authors.initials: GJ
authors.lastname: Cheng