Role of Ambient Hydrogen in HiPIMS-ITO Film during Annealing Process in a Large Temperature Range.

Indium tin oxide (ITO) thin films were prepared by high power impulse magnetron sputtering (HiPIMS) and annealed in hydrogen-containing forming gas to reduce the film resistivity. The film resistivity reduces by nearly an order of magnitude from 5.6 × 10-3 Ω·cm for the as-deposited film to the lowest value of 6.7 × 10-4 Ω·cm after annealed at 700 °C for 40 min. The role of hydrogen (H) in changing the film properties was explored and discussed in a large temperature range (300-800 °C). When annealed at a low temperature of 300-500 °C, the incorporated H atoms occupied the oxygen sites (Ho), acting as shallow donors that contribute to the increase of carrier concentration, leading to the decrease of film resistivity. When annealed at an intermediate temperature of 500-700 °C, the Ho defects are thermally unstable and decay upon annealing, leading to the reduction of carrier concentration. However, the film resistivity keeps decreasing due to the increase in carrier mobility. Meanwhile, some locally distributed metallic clusters formed due to the reduction effect of H2. When annealed at a high temperature of 700-800 °C, the metal oxide film is severely reduced and transforms to gaseous metal hydride, leading to the dramatic reduction of film thickness and carrier mobility at 750 °C and vanish of the film at 800 °C.

[Genome-wide analysis of the LPAAT gene family in Gossypium raimondii and G. arboreum, and expression analysis of its orthologs in G. hirsutum].

Lysophosphatidic acid acyltransferase (LPAAT) which converts lysophosphatidic acid into phosphatidic acid is a key enzyme in biosynthesis pathway of lipid in plants. In this study, we identified 17 members of the LPAAT gene family from genomic data of G. raimondii-D5 and G. arboreum-A2. Analysis of gene structure, chromosome distribution and phylogenetic evolution of LPAAT genes in diploid Gossypium using bioinformatics approaches showed that these genes can be divided into distinct subfamilies based on the distance of their genetic relationship. Moreover, the gene structures were similar within LPAAT subfamily members. The amino acid sequences encoded by LPAAT family genes contained three conserved motifs, including ΦFPEGTR-G binding site and Φ-NHQS- ΦDΦΦ catalytic site. Phylogenetic analysis of LPAAT gene family demonstrated significant differences in evolution of LPAAT in different species. Finally, expression analysis of G. hirsutum ovules in different stages from RNA-seq and qRT-PCR data indicated that LPAAT gene may play a positive role in oil accumulation. Our studies facilitate understanding of the function of LPAAT gene family in Gossypium and selecting better LPAAT genes for further functional validation.