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

The XeCl excimer laser (308 nm) was used for depositing p‐type SrCu2O2 (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 SrCu2O2 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.