Abstract
In this work, electrophoretic deposition (EPD) is reported to form gallium thin film with high deposition rate and low cost while avoiding the highly toxic chemicals typically used in electroplating. A maximum deposition rate of ~0.6 μm/min, almost one order of magnitude higher than the typical value reported for electroplating, is obtained when employing a set of proper deposition parameters. The thickness of the film is shown to increase with deposition time when sequential deposition is employed. The concentration of Mg(NO3)2, the charging salt, is also found to be a critical factor to control the deposition rate. Various gallium micropatterns are obtained by masking the substrate during the process, demonstrating process compatibility with microfabrication. The reported novel approach can potentially be employed in a broad range of applications with Ga as a raw material, including microelectronics, photovoltaic cells, and flexible liquid metal microelectrodes.
Highlights
Gallium and its compounds can find many applications in microelectronics [1], solar cells [2,3], solar water splitting [4,5], microwave circuitry [6], optoelectronics [7], flexible neuroprobes [8], self-repairing electrodes [9], and micro switches [10]
High-quality Ga thin film can be obtained by physical vapor deposition (PVD), while some Ga compounds thin films, such as gallium arsenide (GaAs) and gallium nitride (GaN), can be obtained by chemical vapor deposition (CVD) [12] and pulsed laser deposition [13]
Different from solid particles, the liquid gallium droplets can coagulate with each other shortly after the sonication. Such a colloid of gallium at room temperature completely collapses within a few hours, as evidenced by the precipitate observed on the bottom of the testing tube (Figure 1a) and the clear liquid seen at the side (Figure 1c) after 2 h
Summary
Gallium and its compounds can find many applications in microelectronics [1], solar cells [2,3], solar water splitting [4,5], microwave circuitry [6], optoelectronics [7], flexible neuroprobes [8], self-repairing electrodes [9], and micro switches [10]. Considerable efforts have already been made to Micromachines 2015, 6 deposit gallium thin films, which typically involve electroplating with highly toxic gallium salts. The high cost, low deposition rate and poor scalability have limited the employment of those aforementioned methods in applications, such as solar cells. Electrophoretic deposition (EPD) is known for its low cost, versatility and excellent scalability [14]. As compared with electroplating, whose deposition rate strongly depends on the reduction potential of the species being deposited, the deposition rate control of EPD is more straightforward, which makes it more suitable for co-deposition [15]. EPD can be performed to deposit gallium on various substrates as precursors to obtain the aforementioned functional materials. We communicate successful EPD of Ga thin film with a high deposition rate of. The critical deposition parameters and process compatibility to micro patterning are investigated
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
