Transparent Conducting Electrodes for Optoelectronic Devices: State-of-the-art and Perspectives

This chapter brings a concise review of the transparent conducting materials, films and electrodes (TCM, TCF and TCE, respectively), its state-of-the-art and outlooks ahead. Initial part of the chapter gives a general introduction of the topic, followed by a feasible road map as proposed and collated by the authors based on several other reviews. Fundamental physics behind the transparent conductors is discussed in the latter part. Established and potential oxide based TCMs, namely the transparent conducting oxides (TCOs) are reviewed which are being used commercially and will see application in the near future. Non-conventional TCMs, which are mostly non-TCOs, such as graphene, carbon nanotubes (CNT), metallic nanowires (MNWs) and their hybrids are described in brief. Scalability and large area fabrication which are most important concerns for commercialization of TCMs are discussed. The general prospects are given at the end.

Layered CuI: a path to 2D p-type transparent conducting materials

Zincblende copper iodide, a p-type semiconductor that is transparent in the visible spectral range, has attracted growing attention as a promising material for transparent electronics. While the zincblende γ-phase is...

p-type transparent superconductivity in a layered oxide

Development of p-type transparent conducting materials has been a challenging issue. The known p-type transparent conductors unsatisfy both of high transparency and high conductivity nor exhibit superconductivity. Here, we report on epitaxial synthesis, excellent p-type transparent conductivity, and two-dimensional superconductivity of Li1−xNbO2. The LiNbO2 epitaxial films with NbO2 sheets parallel to (111) plane of cubic MgAl2O4 substrates were stabilized by heating amorphous films. The hole doping associated with Li+ ion deintercalation triggered superconductivity below 4.2 kelvin. Optical measurements revealed that the averaged transmittance to the visible light of ~100-nanometer-thick Li1−xNbO2 was ~77%, despite the large number of hole carriers exceeding 1022 per cubic centimeter. These results indicate that Li1−xNbO2 is a previously unknown p-type transparent superconductor, in which strongly correlated electrons at the largely isolated Nb 4dz2 band play an important role for the high transparency.

Transparent p-Type Semiconductors: Copper-Based Oxides and Oxychalcogenides

While p-type transparent conducting materials (TCMs) are crucial for many optoelectronic applications, their performance is still not satisfactory. This has impeded the development of many devices such as photovoltaics, sensors, and transparent electronics. Among the various p-type TCMs proposed so far, Cu-based oxides and oxychalcogenides have demonstrated promising results in terms of their optical and electrical properties. Hence, they are the focus of this current review. Their basic material properties, including their crystal structures, conduction mechanisms, and electronic structures will be covered, as well as their device applications. Also, the development of performance enhancement strategies including doping/co-doping, annealing, and other innovative ways to improve conductivity will be discussed in detail.

Rational design of transparent p-type conducting non-oxide materials from high-throughput calculations

In this work, high-throughput ab initio calculations are employed to identify the most promising chalcogenide-based semiconductors for p-type transparent conducting materials (TCMs).