Carbon nanotubes (CNT) are grown in anodic aluminum oxide (AAO) and use as field emitters in a triode structure. To fabricate the field-emission triode structure, nanoporous AAO thin layer is first prepared on the Si(100) substrate, followed by the growth of vertically aligned carbon nanotubes in AAO pore channels by electron cyclotron resonance chemical vapor deposition. The SiO 2 dielectric and Al gate electrode layers requires for the triode structure are directly deposited on the CNTs. Reactive ion and wet etches are then used to open the field-emission area in the triode. Scanning electron microscopy and Raman spectroscopy studies reveal that damage to CNT emitters in the etched area is trivial. Field emission properties of CNT emitters are then calculated by solving a set of Maxwell equations with FDTD-PIC method. Calibration between the measured current and computed results is performed to validate the theoretical approach. According to our investigation, 10 CNTs in the explored single triode structure show the best current density of the structure.