title: Optical absorption and photocurrent enhancement in semi-insulating gallium arsenide by femtosecond laser pulse surface microstructuring.
abstract: 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 0.74 μm periodic ripples, and its optical absorption-edge is shifted to a longer wavelength. Meanwhile, the steady photocurrent of irradiated SI-GaAs is found to enhance 50%. The electrical properties of samples are calibrated by van der Pauw method. It is found that femtosecond laser ablation causes a microscale anti-reflection coating surface which enhances the absorption and photoconductivity.
authors.forename: Zhen-Yu
authors.initials: ZY
authors.lastname: Zhao
authors.forename: Zhi-Qiang
authors.initials: ZQ
authors.lastname: Song
authors.forename: Wang-Zhou
authors.initials: WZ
authors.lastname: Shi
authors.forename: Quan-Zhong
authors.initials: QZ
authors.lastname: Zhao