Diamond is not just a gemstone. This crystal can conduct electricity when free charge carriers, electrons and holes, appear in it. But how fast do they move? In scientific papers, numbers vary by tens of times. One lab reports a mobility of 1000 cm²/(V·s), another 4000. Why such chaos?
A group of researchers collected data from many publications and found three main reasons for the confusion. The first is the different electric field at which the mobility was measured. In a weak field, carriers accelerate smoothly; in a strong field, they hit a limit, like sprinters on a short track. The second reason is the choice of formula: different models describe differently how mobility depends on field. The third is how the crystal was excited: with alpha particles, a laser, or an electron beam. It turned out that alpha particles give slightly different results than a laser, and this shifts the final parameters.
The authors proposed a new model for electrons that works over a wide range of fields. For holes, the good old Caughey–Thomas model fit best. They also provided temperature corrections near room temperature. Now engineers designing diamond radiation detectors or high-power electronics can choose the right numbers without guessing.
So scattered data, like pieces of a mosaic, came together into a single picture. Diamond once again proved to be a material with character, but now its character can be described by formulas.
Diamond is one of the best natural insulators, but if you add impurities or irradiate it, it becomes a semiconductor. Moreover, it withstands huge voltages and high temperatures, making it a candidate for future electronics.