An enhanced electron amplifier structure includes a microporous substrate having a front surface and a rear surface, the microporous substrate including at least one channel extending substantially through the substrate between the front surface and the rear surface, an ion diffusion layer formed on a surface of the channel, the ion diffusion layer comprising a metal oxide, a resistive coating layer formed on the first ion diffusion layer, an emissive coating layer formed on the resistive coating layer, and an optional ion feedback layer formed on the front surface of the structure. The emissive coating produces a secondary electron emission responsive to an interaction with a particle received by the channel. The ion diffusion layer, the resistive coating layer, the emissive coating layer, and the ion feedback layer are independently deposited via chemical vapor deposition or atomic layer deposition.

Provided is a substrate treatment apparatus using plasma. The substrate treatment apparatus includes a housing having an inner space in which a substrate is treated, a support member disposed within the housing to support the substrate, a gas supply unit supplying a gas into the housing, a plasma source generating plasma from the gas supplied into the housing, and a baffle unit disposed to surround the support member within the housing, the baffle unit including a baffle in which through holes for exhausting the gas into the inner space of the housing are defined. The baffle is divided into a plurality of areas when viewed from an upper side, and each of portions of the plurality of areas is formed of a metallic material, and each of the other portions of the plurality of areas is formed of a nonmetallic material.

A metasurface element includes a support body and a metasurface formed on a surface of the support body. The metasurface includes a metal pattern that is disposed to emit an electron in response to incidence of an electromagnetic wave, and a metal layer that contains an alkali metal and is formed on the metal pattern. The metal layer extends beyond the metal pattern to reach a region on the surface of the support body, the region being not formed with the metal pattern.

A metasurface element includes a support body and a metasurface formed on a surface of the support body. The metasurface includes a metal pattern that is disposed to emit an electron in response to incidence of an electromagnetic wave, and a metal layer that contains an alkali metal and is formed on the metal pattern. The metal layer extends beyond the metal pattern to reach a region on the surface of the support body, the region being not formed with the metal pattern.