Study on the Use of Silicon Drift Detector to Get Information on Light Emitted by Luminescent Materials

Abstract

Energy dispersive X-Ray detectors are among the most common tools installed on scanning electron microscopes and, as they are sensitive to light, they can be used to get panchromatic cathodoluminescence information. This article presents practical considerations about the parameters to choose to obtain a good cathodoluminescence signal on a silicon drift detector. Probe current is the most important but other parameters of electron microscope and energy dispersive X-Ray detector are also explored. Filament brightness, if not fixed, influences the number of electrons incident on the sample and modifies cathodoluminescence response. Beam voltage and working distance must be adapted to the sample and to the electron microscope geometry. Acquisition and shaping times are important parameters for spectrum quality: the high sensitivity of silicon drift detector to light allows the use of low acquisition times and high shaping times. As cathodoluminescent materials are mostly high band gap materials, charge effects can influence their response and the size of the acquisition area must be carefully chosen. The influence of all these parameters is studied through two scintillating materials. Some examples of application are described to show the potential of this method. They include localization of luminescent particles, a demonstration of the effect of strong electron beam on a needle of material and the characterization of light emitted by a structural defect in a scintillator material.