Properties of strontium copper oxide (SCO) deposited by PLD using the 308nm laser and formation of SCO/Si heterostructures

The XeCl excimer laser (308 nm) was used for depositing ptype SrCu ₂O ₂ (SCO) films by pulsed-laser deposition (PLD) from undoped and Ba-doped (6%) SCO targets. The SCO films were deposited at 300 °C on glass and p-type Si substrates, while the oxygen pressure was kept constant at 5×10 ^-2 Pa and their properties were investigated just after deposition and after annealing at 330 C° in forming gas. The films were amorphous just after deposition but became stoichiometric SrCu ₂O ₂ polycrystalline after annealing and very resistive. The Ba-doped SCO films showed lower transmittance than the undoped ones but for both films the transmittance increased to around 70-80% in the NIR-IR spectrum. The optical energy gap was found to be around 3.24 eV after annealing. SCO films deposited on p-Si exhibited rectifying properties, behaving like p ^--SCO/p-Si heterojunctions and their I-V and C-V characteristics were examined with temperature. An explanation of the diode behaviour is attempted based on materials properties and heterodiode characteristics.