Structure and optical properties of amorphous lead-germanate films developed by pulsed-laser deposition

Lead-germanate materials are attractive systems for photonics applications. In this context, amorphous lead-germanate films were grown by pulsed-laser deposition at different substrate temperatures and oxygen pressures using a glassy target of composition 0.4PbO-0.6GeO(2). Optical and infrared measurements showed that the substrate temperature has a strong influence on the optical quality and stability of the deposited films. An accurate characterization of films was achieved by comparing experimental and simulated transmittance spectra in the infrared, and allowed to probe the structural evolution and variations in composition as a function of oxygen pressure. The results showed that the difference in reactivity of lead and germanium toward oxygen in the laser-produced plasma allows for composition adjustments in the lead-germanate films by varying the oxygen pressure in the deposition chamber.