Pulsed laser deposition of Mg thin films on Cu substrates for photocathode applications

In this study, pulsed laser ablation of pure Mg targets (99.99%) using an XeCl excimer laser (l = 308 nm, t = 30 ns) was used to grow Mg coatings on Cu substrates. A thin layer of Mg (100–200 nm) was deposited in UHVof 5 10 6 Pa to ensure high purity. A second ultra-thin layer of MgO of 10–20 nm was deposited in oxygen at 10 2 Pa pressure to protect the previous layer from atmospheric contamination. Measurements for determining the electron yield of the deposited samples under UV irradiation were performed on a diode structure in another UHV apparatus evacuated to 10 6 Pa.