His research interests are mainly in field electron emission phenomena, field electron emitters, vacuum nanoelectronic devices and cold cathode X-ray tubes. In addition, his research interests are extended to synthesis, characterization and electical property control of carbon nanotubes and graphene. He published more than 200 scietific articles and enrolled 22 international patents and 60 domestic patents. In 2012, he chaired the 25th International Vacuum Nanoelectronics Conference in Jeju Korea.