Accuracy and Repeatability of Linear Measurements using the Field Emission Scanning Electron Microscope (FE-SEM) Built-in Measurement Tool for Nanomaterials and Nano-enabled Products
Alfeche, Dale Mhar B., Bauca, Marianne Therese A., Santillan, Abegail I., Valiente, Ian V., Sito, Princess Joyce A. and Monsada, Araceli M.
DOST-ITDI (Advanced Device and Materials Testing Laboratory-ADMATEL)
DOST Compound, Bicutan, Taguig City, Metro Manila 1631
Corresponding Author: firstname.lastname@example.org; email@example.com; firstname.lastname@example.org
Presented at the 82nd PIChE National Convention
The FE-SEM is an analytical tool used primarily for imaging the surface of a sample. Some FE-SEM systems such as the one housed in ADMATEL has a built-in measurement tool that enables the user to get dimensional information on particular features of interest. ADMATEL’s FE-SEM is capable of acquiring the following measurements: linear, diameter, rectangular length & width and angle. This study focused on diameter measurement only. Accuracy and repeatability of measurements are important especially, for dimensions/sizes of nanomaterials/nano powders that are in the nano-scale. The range of uncertainty must be minimized to ensure that readings are always near the true value. This is a critical parameter on quality control for products and processes that have pass/fail criteria which are dependent on certain physical dimensions. Measurements were obtained from standard polystyrene nanospheres with known nominal diameter. All sample preparation methods and trials were carried out in a class 100k cleanroom with a controlled ambient temperature of 20-25degC and RH of 50-60%. An average diameter value of 61.59nm was obtained from a total of 500 readings spread among 5 analysts. A measurement uncertainty of ±3nm was reported. Calculated mean and measurement uncertainty were close to the true value of the standard sample, thus confirming the accuracy and repeatability of measurements using the FE-SEM’s built-in measurement tool.
Keywords: Repeatability, nanomaterial, nano-scale, polystyrene nanospheres, measurement uncertainty