Exploiting Edge Effect to Control Generation Rate and Breakdown Voltage in Graphene Nanoribbon Field Effect Transistors

Plasmonics - Based on the influence of edge effect and channel shape, two new graphene nanoribbon field effect transistors are presented being useful in high-voltage and highly sensitive optical...     

Ultra-Sensitive Humidity Sensor Based on Optical Properties of Graphene Oxide and Nano-Anatase TiO2

Generally, in a waveguide-based humidity sensors, increasing the relative humidity (RH) causes the cladding refractive index (RI) to increase due to cladding water absorption. However, if graphene oxide (GO) is used, a reverse phenomenon is seen due to a gap increase in graphene layers. In this paper, this interesting property is applied in order to fabricate differential humidity sensor using the difference between RI of reduced GO (rGO) and nano-anatase TiO₂ in a chip. First, a new approach is proposed to prepare high quality nano-anatase TiO₂ in solution form making the fabrication process simple and straightforward. Then, the resulted solutions (TiO₂ and GO) are effortlessly drop casted and reduced on SU8 two channels waveguide and extensively examined against several humid conditions. Investigating the sensitivity and performance (response time) of the device, reveals a great linearity in a wide range of RH (35% to 98%) and a variation of more than 30 dB in transmitted optical power with a response time of only ~0.7 sec. The effect of coating concentration and UV treatment are studied on the performance and repeatability of the sensor and the attributed mechanisms explained. In addition, we report that using the current approach, devices with high sensitivity and very low response time of only 0.3 sec can be fabricated. Also, the proposed device was comprehensively compared with other state of the art proposed sensors in the literature and the results were promising. Since high sensitivity ~0.47dB/%RH and high dynamic performances were demonstrated, this sensor is a proper choice for biomedical applications.     

Picomole Dopamine Detection Using Optical Chips

Plasmonics - Precise detection of dopamine is essential in medical applications to diagnose many diseases such as Parkinson’s disease. Here, a new optical approach based on surface plasmon...