Microstructure and properties of mono-crystalline germanium enhanced by high-current pulsed electron beam.

High current pulsed electron beam (HCPEB) technology was applied to irradiate the surface of mono-crystalline Ge wafers (Ge (100) and Ge (111)) with different orientations, and the microstructure and properties of the irradiated surface were analyzed in detail. The results show that after HCPEB irradiation, numerous molten pits and local microcracks were produced on the surface of mono-crystalline Ge, and the pit density decreased with the increase of irradiation pulses. TEM observations indicated that after irradiation, the defects are mainly vacancy group defects and dislocation rings, and Ge nanocrystals with uniform size distribution are produced. HCPEB irradiation also formed self-assembled nanostructures on the surface of Ge. Cross section TEM indicated that the 250 nm deep defect channels were under the quantum dots, which confirms the formation mechanism of self-assembled nanostructures. The photoluminescence results indicated that the irradiated mono-crystalline Ge still has blue emission properties, and the luminescence mechanism is the quantum confinement effect of Ge nanocrystals embedded in slightly oxidized or nitrided amorphous structures. • HCPEB irradiation can induce the proliferation of crystal defects and the formation of neatly arranged microcrack. • HCPEB irradiation induced numerous supersaturated vacancy defects in mono-crystalline Ge. • HCPEB irradiation induced the formation of nanocrystals on the Ge surface. • HCPEB irradiation induced the formation of self-assembled nanostructures on Ge surface. • After HCPEB irradiation, the blue light emission phenomenon of photoluminescence appeared in mono-crystalline Ge. [ABSTRACT FROM AUTHOR]