We prepare CuCrO₂ thin films with magnesium and nitrogen dopants. The solid state reaction method is employed to produce CuCrO₂ targets with three different concentrations of Mg (0%, 2.5%, and 5%). The targets are used in an RF sputtering system to prepare thin films in the presence of N₂ as the reactive gas. In this manner, Mg and N atoms, respectively, replace Cr and O sites in the CuCrO₂ structure and enhance the electrical and optical properties of the host material. This cationic-anionic substitution yields a superior hole transport and results in an increased conductivity of ∼278 S cm⁻¹ which is considered as a record for p-type conductivity in transparent conducting oxides. Moreover, the co-doped CuCrO₂ demonstrates a bandgap of 3.52 eV and a transmittance of about 69% in the visible region.

We propose and fabricate a heterojunction between Al-doped ZnO and (Mg, N)-doped CuCrO₂ thin films using the sputtering deposition method. These materials possess wide bandgap that makes them transparent in the visible light but excellent UV-absorbers. On the other hand, the high conductivity of these materials, respectively as n-type and p-type transparent conducting oxides, facilitates the charge transport. We show that the p–n junction fabricated from these materials has the potential to act as a high-performance UV photovoltaic photodetector. The proposed structure, demonstrates fast responses in order of sub seconds, photosensitivity of ~ 41,000, responsivity of 1.645 mA/W, and a detectivity of 3.52 × 10¹² Jones that are significantly improved in comparison with the Al-doped ZnO photoconductor. This excellent improvement is attributed to the capability of the photovoltaic configuration that creates a built-in voltage and facilitates the charge separation and collection rather than recombination in the photoconductor configuration.

Metamaterial photonic integrated circuits with arrays of hybrid graphene–superconductor coupled split-ring resonators (SRR) capable of modulating and slowing down terahertz (THz) light are introduced and proposed. The hybrid device’s optical responses, such as electromagnetic-induced transparency (EIT) and group delay, can be modulated in several ways. First, it is modulated electrically by changing the conductivity and carrier concentrations in graphene. Alternatively, the optical response can be modified by acting on the device temperature sensitivity by switching Nb from a lossy normal phase to a low-loss quantum mechanical phase below the transition temperature (T_c) of Nb. Maximum modulation depths of 57.3% and 97.61% are achieved for EIT and group delay at the THz transmission window, respectively. A comparison is carried out between the Nb-graphene-Nb coupled SRR-based devices with those of Au-graphene-Au SRRs, and significant enhancements of the THz transmission, group delay, and EIT responses are observed when Nb is in the quantum mechanical phase. Such hybrid devices with their reasonably large and tunable slow light bandwidth pave the way for the realization of active optoelectronic modulators, filters, phase shifters, and slow light devices for applications in chip-scale future communication and computation systems.