Physical characterization of n-GaAs on p-Si formed by low-temperature pulsed-laser deposition

摘要

Stoichiometry, texture, surface features, I-V characteristic, and optical responsivity were studied of thin-film n-GaAs deposited onto p-type Si at room temperature. Low-temperature pulsed-laser deposition using a neodymium doped yttrium aluminum garnet laser (532 nm, 6 ns, 10 Hz) was employed to form the heteropairing. The film is stoichiometric, mainly of amorphous nature including some crystalline sections, and, despite droplets, exhibits an optically smooth surface. Rectification and photodiode properties for alternating as well as direct current experiments were established in an almost scholastic manner, which cannot be attributed to the previously investigated p-GaAs-Si. Hence, the ablation of electron rich GaAs is apparently the way of choice to form operative GaAs/Si junction devices. The work further reveals that intrinsic sample features might be different for alternating and direct photocurrent measurements.