Laser-induced nano-oxidation on hydrogen-passivated Ge (100) surfaces under a scanning tunneling microscope tip

Laser-induced nano-oxidation on hydrogen-passivated Ge (100) surfaces under a scanning tunneling microscope tip in air has been investigated. A 532 nm Nd:YAG pulsed laser with a pulse duration of 7 ns was used. A 2×2 oxide dot array with dot sizes between 20 and 30 nm and an oxide single line with a width less than 30 nm have been created using an electrochemical-etched tungsten tip under laser irradiation. The modified regions were characterized by atomic force microscope. The apparent depth of oxide layer as a function of laser intensity has been studied. The advantages and drawbacks of using a continuous wave laser and a pulsed laser will be discussed.