Scanning probe microscope

摘要

A scanning probe microscope includes a laser diode (1a) as a light source for emitting light lower in energy level than band gap of semiconductor as a sample. Laser light (2) emitted therefrom should be of wavelength larger in value than a wavelength A calculated as follows: lambd=h.c/Eg where h is Planck's constant, c represents speed of light and Eg represents band gap. When the semiconductor as a sample is silicon, the band gap thereof is 1.12 eV, thus calculating the wavelength lambd at 1.107 mum. The laser diode (1a) should be such that the laser light (2) emitted therefrom is of wavelength larger in value than lambd. It is therefore allowed to avoid emission of light higher in energy level than the band gap of silicon as a sample and eventually, avoid generation of photoelectric current in the sample.