METHOD AND DEVICE FOR MEASUREMENT OF UNOCCUPIED ENERGY LEVELS OF SOLID
While progressively changing the kinetic energy (acceleration energy) of an electron beam within the range of 0-5 eV, spectra are obtained by measuring the intensity of near-ultraviolet and visible light having a wavelength of 180-700nm that is emitted from a solid sample, such as an organic semiconductor, during irradiation with the electron beam. A peak is detected in the spectra, and the energy level thereof is the unoccupied energy level of the sample. In particular, the energy at the rise of the initial peak represents the electron affinity of the sample. Because the energy of the electron beam irradiated onto the sample is less than or equal to 5eV, even organic semiconductor samples will be largely undamaged.