2017, Vol.27, No.2

Journal of the Korean Crystal Growth and Crystal Technology 2023 KCI Impact Factor : 0.19

pISSN : 1225-1429 / eISSN : 2234-5078
https://journal.kci.go.kr/jkcgct

AlN single crystal was thermally treated at 1600, 1700 and 1800oC in the ambient pressure of under 100 torr. AlN single crystal was obtained by PVT (Physial Vapor Transport) method using by a facility having a growth part which was heated by RF (Radio Frequency) induction heating. The single crystal specimens surface was evaluated by optical microscope and it was recognized that their morphology was varied with the heat treatment temperature and a set ambient pressure. In this report, the optical microscopic results were reported. According to the increase of temperature the crystal surface was etched thermally. It was evaluated by appearance of small pits on the crystal surface.

Two milling methods, dry vibration milling and wet ball milling, were used to prepare Na2/3(Ni1/3Mn2/3)O2 powders as a cathode material for sodium ion batteries. The morphology and electrochemical property of the two powders with different milling processes were compared to each other. The particle size is less than 1 μm in the dry vibration milled powder, while lots of larger particles than 1 μm were found in the wet ball milled one. The single phase of Na2/3(Ni1/3Mn2/3)O2 was obtained in the temperature range of 875~900 o C. The discharge capacity and discharge voltage of the powder prepared by the dry process were higher than those of one prepared by the wet process.

Honeycomb-shaped Ag-grid transparent conductive electrodes (TCEs) were fabricated using two different processes, high density plasma etching and lift-off, and the optical and electrical properties were compared according to the fabrication method. For the fabrication of the Ag-grid TCEs by plasma etching, etch characteristics of the Ag thin film in 10CF4/5Ar inductively coupled plasma (ICP) discharges were studied. The Ag etch rate increased as the power increased at relatively low ICP source power or rf chuck power conditions, and then decreased at higher powers due to either decrease in Ar + ion energy or Ar + ion-assisted removal of the reactive F radicals. The Ag-grid TCEs fabricated by the 10CF4/5Ar ICP etching process showed better grid pattern transfer efficiency without any distortion or breakage in the grid pattern and higher optical transmittance values of average 83.3 % (pixel size 30 μm/line width 5 μm) and 71 % (pixel size 26 μm/line width 8 μm) in the visible range of spectrum, respectively. On the other hand, the Ag-grid TCEs fabricated by the lift-off process showed lower sheet resistance values of 2.163 Ω/□ (pixel size 26 μm/line width 8 μm) and 4.932 Ω/□ (pixel size 30 μm/line width 5 μm), respectively.