KAUST researchers demonstrate 85% transparent rectifier
While monolayer MoS2 is known to be transparent, the researchers investigated the use of transparent and aluminium doped zinc oxide (AZO) contacts whose composition they tuned through atomic layer deposition to achieve optimal conductivity and band-offsets with the MoS2 layer.
In their paper “Large-Area Chemical Vapor Deposited MoS2 with Transparent Conducting Oxide Contacts toward Fully Transparent 2D Electronics” published in the journal of Advanced Functional Materials, the researchers report fully transparent TCO/MoS2 2D electronics with an average visible-range transmittance of 85% (92% for the MoS2 monolayer and 85% for the whole stack).
Patterning the MoS2 films by plasma etching, they fabricated various transparent devices and circuits, including thin film transistors and a rectifier (a NMOS inverter) where the transparent oxide layers including 165nm-thin AZO contacts used for both the source/drain and gate electrodes, and a 55nm HfO2 transparent gate dielectric were subsequently deposited by atomic layer deposition.
The transistors exhibited a high mobility of 4.2 cm2 V−1 s−1, fast switching speed, a very low threshold voltage (0.69V) and a large switching ratio (4×108). Values that the authors claim to be record-breaking for monolayer CVD-processed MoS2 transistors. The transparent fast switching inverters exhibited a gain of 155 at a supply voltage of 10V.
Next, the researchers aim to prove that their fabrication method is scalable to larger and more complex circuits, to open the path for a wider adoption of 2D semiconductors combined with transparent conducting oxides. Applications could include the fabrication of completely translucent components for transparent displays, smart windows and other concealed circuits
Kaust – www.kaust.edu.sa
Related articles:
Smart window tints and acts as transparent battery
Printable silver nanowire ink enables transparent and flexible conductive patterns
Transparent capacitive touch sensor flexes, stretches and detects 3D shapes