Principle of CCD and Application in Transmission Electron Microscope
Abstract: Charge-coupled devices (CCDs) work on the principle of charge transfer. CCD image sensors have high sensitivity for the detection of almost single photons and low noise characteristics with excellent linearity between the input light power and the output signal. Therefore, they are widely used in microscopes, telescopes, and consumer video or still cameras. CCD image sensors output an image signal by using charges that are produced from the electron–hole pairs generated by light in the semiconductor, and the charges are transferred by the charge transfer method. The electron–hole pairs can also be generated by X-rays and electron beams. It is possible to obtain an electron image by direct electron irradiation of the CCD image sensor present inside a transmission electron microscope. In this lecture, the principle and structure of a CCD image sensor are described; its application when used inside a transmission electron microscope for obtaining images via direct single electron detection is also described.
Key words: CCD, Charge transfer, Image sensor, Transmission electron microscope, Single electron detection