No abstract

No abstract

Device engineering for high-performance, low-voltage operating organic field effect transistor on plastic substrate. Flexible and Printed Electronics, 2(4), [045004].

-A fully integrated passive mixer suitable for 2.45 GHz low consumption and low cost applications is proposed and demonstrated in a 90 nm CMOS technology. An original operating principle is adopted which is based on the use of a local oscillator square signal exhibiting a duty cycle less than 1/4. By using such a LO driving, the mixer operates as a sampler and can theoretically achieve a voltage conversion gain of 0 dB. This mixer has been integrated in a complete monolithic receiver. According to simulations, measurements demonstrate improvements of 5 dB on gain and 3 dB on noise figure without any linearity degradation and any additional cost, when compared to a common LO driving of 1/2 duty cycle.

The high performance air stable organic semiconductor small molecule dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (DNTT) was chosen as active layer for field effect transistors built to realize flexible amplifier circuits. Initial device on rigid Si/SiO 2 substrate showed appreciable performance with hysteresis-free characteristics. A number of approaches were applied to simplify the process, improve device performance and decrease the operating voltage: they include an oxide interfacial layer to decrease contact resistance; a polymer passivation layer to optimize semiconductor/dielectric interface and an anodized high-k oxide as dielectric layer for low voltage operation. The devices fabricated on plastic substrate yielded excellent electrical characteristics, showing mobility of 1.6 cm 2 /Vs, lack of hysteresis, operation below 5 V and on/off current ratio above 10 5. An OFET model based on variable ranging hopping theory was used to extract the relevant parameters from the transfer and output characteristics, which enabled us to simulate our devices achieving reasonable agreement with the measurements