Ultrafast properties of femtosecond-laser-ablated GaAs and its application to terahertz optoelectronics.

We report on the first terahertz (THz) emitter based on femtosecond-laser-ablated gallium arsenide (GaAs), demonstrating a 65% enhancement in THz emission at high optical power compared to the nonablated device. Counter-intuitively, the ablated device shows significantly lower photocurrent and carrier mobility. We understand this behavior in terms of n-doping, shorter carrier lifetime, and enhanced photoabsorption arising from the ablation process.

Optical absorption and photocurrent enhancement in semi-insulating gallium arsenide by femtosecond laser pulse surface microstructuring.

We observe an enhancement of optical absorption and photocurrent from semi-insulating gallium arsenide (SI-GaAs) irradiated by femtosecond laser pulses. The SI-GaAs wafer is treated by a regeneratively amplified Ti: Sapphire laser of 120 fs laser pulse at 800 nm wavelength. The laser ablation induced 0.

[Effect of post-annealing on the structure and fluorescence properties of YMnO3 thin films].

YMnO3 thin films deposited on Si (100) substrate by pulsed laser deposition at room temperature were annealed at different temperatures. The microstructure and fluorescent emission properties of these films were studied using XRD and UV-Vis spectroscopy. The results show that polycrystalline YMnO3 thin films can be obtained through post-annealing, in which hexagonal phase and orthorhombic phase coexist.

[Fluorescence emission properties of Ni-doped ZnO films].

Ni-doped ZnO films were deposited on Si(100) by pulsed laser deposition(PLD) at room temperature. Fluorescence emission properties of the films were measured using VARAIN Cary-Eclips 500 fluorescence spectrum analyzer. Two peaks centered respectively at about 360 and 380 nm were observed.

[Photoluminescence spectrum of oxygen and nitrogen-doped Si-based film].

O and N-doped amorphous Si-based films were prepared by magnetron sputtering. The photoluminescence (PL) spectra from the films were measured. A series of intense PL bands located in red, green, blue, violet and ultraviolet regions were observed, whose intensities were affected by the contents of O and N and the temperature of the substrate (Ts) during deposition.