Experimental Studies on Low-Pressure Plane-Parallel Hollow Cathode Discharges

Black TiO2 Thin Films Production Using Hollow Cathode Hydrogen Plasma Treatment: Synthesis, Material Characteristics and Photocatalytic Activity

“…This is an interesting result and probably occurred due to the bombardment of high energy hydrogen ions on the film surface, which can cause a chemical etching of the film surface by generation of volatile species such as OH (see Figure 2a). Also, due to the high energy gained by hydrogen ions when passing through the cathodic plasma sheath (higher than 200 eV [35,36]), some ions can be implanted at depths of several nm, promoting the disordering by formation of oxygen vacancies (V o ) (see Figure 2b). The combination of these two phenomena could be responsible for the slight thickness decrease, verified by the profilometry analysis.…”

“…As an alternative to expensive high-density plasma sources such as ICP and electron cyclotron resonance (ECR) plasma, hollow cathode-based plasmas have arisen [35,36]. These plasmas are attractive due to a simple modification of the biased electrode (cathode), from the usual plane geometry to a hollow configuration which significantly enhances the ionization efficiency of the gas discharge at lower pressures.…”

“…These plasmas are attractive due to a simple modification of the biased electrode (cathode), from the usual plane geometry to a hollow configuration which significantly enhances the ionization efficiency of the gas discharge at lower pressures. This occurs because of electrostatic trapping of electrons in the discharge volume called hollow cathode effect (HCE), which promotes a drastic increase in ionization and dissociation processes [35][36][37][38]. Various applications such as thin film deposition [35], material etching [36], and activation of surfaces [35] have benefited from this plasma technology.…”

“…This occurs because of electrostatic trapping of electrons in the discharge volume called hollow cathode effect (HCE), which promotes a drastic increase in ionization and dissociation processes [35][36][37][38]. Various applications such as thin film deposition [35], material etching [36], and activation of surfaces [35] have benefited from this plasma technology. Thus, the hollow cathode hydrogen plasma (HCHP) may be interesting for blackening TiO 2 material process due to its potential in generate highly reactive H 2 plasmas and the lack of studies in the literature using this type of plasma source.…”

Range and similarity of hollow cathode discharge in argon

“…This phenomenon was first observed by Townsend in 1953 [1] and later was called 'hollow cathode effect' or 'hollow cathode mode' (HCM) [2]. Although HCM has been found for >60 years, many investigations on HCD are still performed [3][4][5][6][7][8][9][10][11][12][13].…”