Editors: | F. Kongoli, F. Marquis, N. Chikhradze, T. Prikhna, M. De Campos, S. Lewis, S. Miller, S. Thomas. |
Publisher: | Flogen Star OUTREACH |
Publication Year: | 2022 |
Pages: | 290 pages |
ISBN: | 978-1-989820-68-1(CD) |
ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
Modern thermoelectric devices tend to use inexpensive, environmentally friendly and CMOS compatible materials such as silicon. To improve the thermoelectric characteristics of silicon, researchers are trying to reduce its thermal conductivity using various nanostructuring techniques [1]. However, most of these methods are of limited effectiveness because they are expensive and destroy the internal structure of silicon.
Considering that the calculated thermal conductivity of a system based on a thin silicon film with nanorods to about 50-60% of its initial thermal conductivity with practically unchanged electrical conductivity [2], it is proposed to use silicon nanophonic metamaterials for solution of the urgent problem of creation projection liquid crystal microdisplays with an active matrix of thin-film transistors for head up displays under direct sunlight.
It was investigated in model experiments the possibility of nanophonic metamaterials creation in the form of columnar nanostructures (a periodic set of silicon pillars) on thin poly-silicon films using anisotropic plasma etching through a self-aligned mask, which is a set of gold nanodroplets which is created by vacuum deposition of a thin gold film on a silicon wafer followed by annealing at 500 °C without removal of the samples to air.
The films were obtained by vacuum deposition of gold in Auto 500FL vacuum deposition unit at the substrate temperature of 200 ° C in a vacuum of 1.3 MPa [3].
The samples were etched in aqua regia and washed in deionized water.
The surface morphology was studied using high-resolution scanning electron microscopes JSM 7500 and Supra 25, as well as using AIST-NT and AV 633 atomic force microscopes.
As a result of the analysis of experimental data, it was determined that the optimal surface density of gold nanodroplets with a diameter of 20-50 nm is 2.7-3 * 109 cm-2.
The use of the studied method of nanoscale modification of the surface of thin polysilicon films in order to implement the properties of nanophonic metamaterials in TFT fits well into the traditional microelectronic technology and, as it seems, should not have any significant effect on electrical characteristics of TFT, while reducing the heating of the liquid crystal from TFTs in projection microdisplays.
This research was financially supported by the RFBR grant (Project № 19-07-00456).