His research includes SiGe/GeSn epi/photonics, stacked 3D transistors, device/circuit thermal simulation (physics-based and machine learning-based), IGZO TFT, and MIM/FTJ/MTJ/SOT/DRAM memory. He demonstrates the tallest transistor (16 stacked channels), the record high 2,400,000 cm2/Vs electron mobility in strained Si, the first Si-capped SiGe/Ge channels with 3x mobility enhancement (in 5nm node production now), the first CVD GeSn outperforming MBE in terms of hole mobility, the first stacked GeSn/GeSi channel GAA(nanosheet/nanowire) transistors, and the first Si/SiGe/SiC MIS LED/photodetectors. He also invented the tree/E transistors, beyond Stacked GAA. He has 616+ papers (246+ journal papers, 28 IEDM, 10VLSI), 63 US patents, 2 China patents, 45 Taiwan ROC patents, more than 5929 citations with h-index=32, 42 Ph.D. graduates, and 132 master graduates. He has 6 graduate students as professors (2NTU, 1 NTNU, 1 NCHU, 1 NDHU, 1 NJUST), and 3 postdocs as professors (1 NTU, 1 NCU, 1 CGU). Currently, he is advising 16 PhD students and 13 masters.