Vertically integrated amorphous silicon color sensor arrays

Large-area color sensor arrays based on vertically integrated thin-film sensors were realized. The complete color information of each color pixel is detected at the same position of the sensor array without using optical filters. Sensor arrays consist of amorphous silicon thin-film color sensors integrated on top of amorphous silicon readout transistors. The spectral sensitivity of the sensors is controlled by the applied bias voltage. The operating principle of the color sensor arrays and the influence of device design on spectral sensitivity are described. Furthermore, the image quality of the sensor arrays is analyzed by measurements of the line spread function and the modulation transfer function.     

5-Fluorouracil, folinic acid, etoposide and cisplatin chemotherapy for locally advanced or metastatic carcinoma of the oesophagus

38 patients with advanced oesophageal carcinoma were treated with intravenous (i.v.) folinic acid (300 mg/m2), 5-fluorouracil (500 mg/m2), etoposide (100 mg/m2), and cisplatin (30 mg/m2) (FLEP), on days 1, 2 and 3, every 22-28 days. 26 patients had locally advanced disease (LAD) and 12 had metastatic disease (M1). Oesophagectomy was planned for patients with LAD in case of tumour regression after chemotherapy, while patients with M1 disease received chemotherapy only. The overall remission rate was 45% (17/38) including four clinical and two pathologically confirmed complete remissions. 16 patients underwent oesophagectomy, 12 after response to FLEP, and 4 after FLEP and subsequent irradiation +/- 5-fluorouracil/mitomycin. Toxicity was mainly haematological, with WHO grade 3 and 4 leukocytopenia in 50% and thrombocytopenia in 31% of the patients. Two treatment-related deaths were observed; one due to chemotherapy and one postoperatively. Median survival time of LAD patients was 13 months, and actuarial 2-year survival was 31%. Patients with complete tumour resection after FLEP had a median survival time of 18 months and a 2-year survival rate of 42%. Median survival of M1 patients was 6 months. FLEP is an active combination for oesophageal cancer, especially when used preoperatively in LAD.     

Ambipolar microcrystalline silicon thin-film transistors

Hydrogenated microcrystalline silicon (µc-Si:H) has recently received significant attention as a promising material for thin-film transistors (TFTs) in large area electronics due to its high electron and hole charge carrier mobilities. We report on ambipolar TFTs based on microcrystalline silicon prepared by plasma-enhanced chemical vapor deposition at temperature of 160 °C with high electron and hole charge carrier mobilities of 40 cm²/Vs and 10 cm²/Vs, respectively. The ambipolar microcrystalline silicon TFTs provide a simple route in realizing large area integrated circuits at low cost. The electrical characteristics of the ambipolar microcrystalline silicon TFTs will be described and the first results on ambipolar inverters will be presented. The influence of the ambipolar TFT characteristics on the performance of the inverter will be also discussed.     

On the interplay of cell thickness and optimum period of silicon thin‐film solar cells: light trapping and plasmonic losses

Light trapping and photon management in honeycomb‐textured microcrystalline silicon solar cells are investigated experimentally and by modeling of the manufacturing process and the optical wave propagation. The solar cells on honeycomb‐textured substrates exhibit short circuit current densities exceeding 30 mA/cm² and energy conversion efficiencies of up to 11.0%. By controlling the fabrication process, the period and height of the honeycomb‐textured substrates are varied. The influence of the honeycomb substrate morphology on the interfaces of the individual solar cell layers and the quantum efficiency is determined. The optical wave propagation is calculated using 3D finite difference time domain simulations. A very good agreement between the optical simulation and experimental results is obtained. Strategies are discussed on how to increase the short circuit current density beyond 30 mA/cm². In particular, the influence of plasmonic losses of the textured silver (Ag) reflector on the short circuit current and quantum efficiency of the solar cell is discussed. Finally, solar cell structures with reduced plasmonic losses are proposed. Copyright © 2015 John Wiley & Sons, Ltd.