Averaging Pixel Current Adjustment Technique for Reducing Fixed Pattern Noise in the Bolometer-Type Uncooled Infrared Image Sensor.

In this paper, we propose an averaging pixel current adjustment technique for reducing fixed pattern noise (FPN) in the bolometer-type uncooled infrared image sensor. The averaging pixel current adjustment technique is composed of active pixel, reference pixel, and calibration circuit. Polysilicon resistors were used in each active pixel and reference pixel. Resistance deviation among active pixels integrated with the same resistance value cause FPN. The principle of the averaging pixel current adjustment technique for removing FPN is based on the subtraction of dark current of the active pixel from the dark current of the reference pixel. The subtracted current is converted into the voltage, which contains pixel calibration information. The calibration circuit is used to adjust the calibration current. After calibration, the nano-ampere current is output with small deviation. The proposed averaging pixel current adjustment technique is implemented by a chip composed of a pixel array, a calibration circuit, average current generators, and readout circuits. The chip was fabricated using a standard 0.35 µm CMOS process and its performance was evaluated.

On-film formation of bi nanowires with extraordinary electron mobility.

A novel stress-induced method to grow semimetallic Bi nanowires along with an analysis of their transport properties is presented. Single crystalline Bi nanowires were found to grow on as-sputtered films after thermal annealing at 260-270 degrees C. This was facilitated by relaxation of stress between the film and the thermally oxidized Si substrate that originated from a mismatch of the thermal expansion. The diameter-tunable Bi nanowires can be produced by controlling the mean grain size of the film, which is dependent upon the thickness of the film. Four-terminal devices based on individual Bi nanowires were found to exhibit very large transverse and longitudinal ordinary magnetoresistance, indicating high-quality, single crystalline Bi nanowires. Unusual transport properties, including a mobility value of 76900 cm(2)/(V s) and a mean free path of 1.35 mum in a 120 nm Bi nanowire, were observed at room temperature.

Finite size effect on hydrogen gas sensing performance in single Pd nanowires.

We present the hydrogen sensing performance of individual Pd nanowires grown by electrodeposition into nanochannels of anodized aluminum oxide (AAO) templates investigated as a function of the nanowire diameter. Four-terminal devices based on individual Pd nanowires were found to successfully detect hydrogen gas (H(2)). Our experimental results show that the H(2) sensing sensitivity increases and the response time decreases with decreasing diameter of Pd nanowires with d = 400, 200, 80 and 20 nm, due to the high surface-to-volume ratio and short diffusion paths, respectively. This is in qualitatively good agreement with simulated results obtained from a theoretical model based on a combination of the rate equation and diffusion equation.