We have proposed a 128-channel silicon-based optical phased array (OPA) chip with an overall antenna, and a large two-dimensional scanning range of 104.0° × 17.6° was achieved.

Due to the advantages of fast scanning speed, good stability, flexible pointing, high resolution, small size and low cost, optical phased array has become a potential key component of beam scanners. The effective aperture of optical phased array determines properties such as divergence angles and ranging distance, and how to achieve it has been of interest to researchers. In this letter, we have designed and fabricated a 1024-channel passive optical phased array chip. A small divergence angle (0.05 $^{\circ }\,\,\times 0.04^{\circ }$ ) has been achieved by adopting a Si ₃ N ₄ perturbation grating structure on Si waveguide. Based on this chip, we have built a coherent detection demonstration system and carried out relevant experiments with it.

In this paper, the slanting silicon nanohole (SiNH) structure is systematically designed and analyzed by simulation using the finite-element method. The slanting angle of the SiNH structure is fixed at 40° based on the Si(111) wafer. The impact of the SiNH diameter (D) and structural periodicity (P) on the light absorption has been examined. It is found that the absorption is significantly enhanced due to the much suppressed light reflection on the top surface and the strong light trapping ability of the slanting SiNH structure. At the P of 700 nm and D/ P ratio of 0.85, the optimal structural parameters are achieved with the highest ultimate efficiency of 32.9%. It is higher than that of the vertical SiNH structure counterpart which has a value of 29.7%. The physical mechanism of the enhanced light absorption is also discussed.

In this paper, we have demonstrated the crystallization and simultaneous formation of the nanocone structure on the 1.6 mu m thick amorphous silicon (a-Si) film using a one-step femtosecond laser annealing approach. The a-Si layer is crystallized after the annealing process, as confirmed from their Raman spectra. Meanwhile, the conical structures with diameters ranging from 160 nm to 1.4 mu m are formed upon laser beam irradiation at different fluences, as deduced from scanning electron microscope and atomic force microscope characterization. The highest absorption is achieved when the sample is irradiated with a laser fluence of 588 mJ cm(-2). The developed process has potential applications in the fabrication of high efficiency and low cost Si thin-film solar cells. Moreover, the physics and mechanism involved in the laser annealing process are also discussed.

In this letter, gate-all-around vertical nanowire (NW) polycrystalline silicon (poly-Si) thin-film transistors (TFTs) are demonstrated using a CMOS-compatible process. Both Nand P-TFT devices (with gate length down to 100 nm and a wire diameter of ~30 nm) exhibit good transistor performance, e.g., high I_on/I_off ratio of >; 10⁶, low subthreshold slope (SS ~ 100 mV/dec), and reasonable drain-induced barrier lowering [(DIBL); ~50 mV/V] with a wire diameter of ~30 nm. Inverters have been successfully fabricated based on the poly-Si NW TFTs, exhibiting well-behaved transfer characteristics.