2010, Vol.20, No.6

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

After the specimen of A-site defect perovskite La1/3NbO3 single crystal was manufactured, the dielectric properties were studied between the temperature range of 10 and 800 K. The dielectric anomaly appeared at 50 K and 650 K, and, at about 650 K, the thermal hysteresis of dielectric constant was shown. The ac-conductivity of bulk showed the lowest activation energy of 0.43 eV at 560~690 K. Based on the results, it is assumed that the dielectric anomaly at 50 K and 650 K was due to the antiparallel shift of Nb 5+-ion and the rearrangement of La 3+-ion, respectively.

Polycrystalline silicon (pc-Si) films are fabricated and characterized for application to pc-Si thin film solar cells as a seed layer. The amorphous silicon films are crystallized by the aluminum-induced layer exchange (ALILE) process with a structure of glass/Al/Al2O3/a-Si using various thicknesses of Al2O3 layers. In order to investigate the effects of the oxide layer on the crystallization of the amorphous silicon films, such as the crystalline film defects and the crystal grain size, the Al2O3 layer thickness are varied from native oxide to 50 nm. As the results, the defects of the poly crystalline films are increased with the increase of Al2O3 layer thickness, whereas the grain size and crystallinity are decreased. In this experiments, obtained the average pc-Si sub-grain size was about 10 μm at relatively thin Al2O3 layer thickness (≤ 16 nm). The preferential orientation of pc-Si sub-grain was <111>.

The Calcium-aluminate electride thin films on the quartz substrates was coated by sol-gel process. The crystallization of the C12A7 thin film was observed at 800oC and high density C12A7 thin film was achieved on heat treatment at 1,200oC for 1 hour. The reduction heat treatment of C12A7 thin film could be converted from insulator to conductor and the electrical conductivity was 120 S/cm in the C12A7 thin film heat treated at 1,200oC with H2 gas for 48 hours.