Question

explain what optoelectronics based gas sensor is and how graphene can be fabricated into the active devices to engineer the effective optical properties.

Answer 1

Answer:

Optoelectronics (or optronics) is the study and application of electronic devices and systems that source, detect and control light, usually considered a sub-field of photonics. An optoelectronic gas sensor based on optodes, where multiple separate photosensitive elements and an Opto-transmitter located centrally between them are integrated into or onto a semiconductor substrate is characterized in that the photosensitive elements lie in one plane in the substrate, and together with a lateral emission area of the Opto-transmitter emitting light laterally, they are covered by sections of the optode material whose thickness and refractive index are selected so that light emitted laterally from the emission area is guided to the photosensitive elements by total reflection in the optode material in each transmission branch.

Graphene is a promising next-generation conducting material with the potential to replace traditional electrode materials such as indium tin oxide in electrical and optical devices. It combines several advantageous characteristics including low sheet resistance, high optical transparency, and excellent mechanical properties. Recent research has coincided with increased interest in the application of graphene as electrode material in transistors, light-emitting diodes, solar cells, and flexible devices. However, for more practical applications, the performance of devices should be further improved by the engineering of graphene films, such as through their synthesis, transfer, and doping.

Scalable fabrication of high-quality graphene devices is highly desired and important for the practical applications of graphene material. Graphene devices are massively fabricated on SiO2/Si substrate through an efficient process, which combines large-scale growth of monolayer graphene on Pt foil, modified bubbling transfer, and photolithography-based device fabrication.