Method of using an environmental transmission electron microscope

摘要

An environmental transmission electron microscope (ETEM) suffers from gas-induced resolution deterioration. Inventors conclude that the deterioration is due to ionization of gas in the sample chamber of the ETEM, and propose to use an electric field in the sample chamber to remove the ionized gas, thereby diminishing the gas-induced resolution deterioration. The electric field need not be a strong field, and can be caused by, for example, biasing the sample with respect to the sample chamber. A bias voltage of 100 V applied via voltage source is sufficient for a marked improvement the gas-induced resolution deterioration. Alternatively an electric field perpendicular to the optical axis can be used, for example by placing an electrically biased wire or gauze off-axis in the sample chamber.

主权项

1. A method of using an environmental transmission electron microscope, the environmental transmission electron microscope comprising:
an electron source for generating a beam of electrons; a condenser system for directing the beam of electrons on a sample, the sample located in a sample chamber; an imaging system for imaging electrons transmitted through the sample on a detector system; and a gas regulating system for regulating a gas pressure and a gas composition in the sample chamber, the gas regulation system maintaining a pressure of between 0.5 and 50 mbar in at least part of the sample chamber, the environmental transmission electron microscope suffering from gas-induced resolution deterioration, the method comprising: generating a beam of electrons directing the beam of electrons on the sample in the sample chamber; forming an image using electrons imaging transmitted through the sample and onto the detector system; and removing ionized gas from the sample chamber by generating an electric field in the sample chamber, as a result of which gas-induced resolution deterioration is diminished.