Growth conditions of β-FeSi_2 single crystals by chemical vapor transport

摘要

The chemical vapor transport (CVT) with iodine as a transport agent used to grow the β-iron disilicide (FeSi_2) single crystals in the present study. To examine the growth conditions, the source temperature is fixed at 1323 K, and the temperatures of the crystallization zone are changed from 923 to 1223 K. The results show that Si, ε-FeSi, β-FeSi_2 and α-FeSi_2 phases are formed in the ranges of 923-1108, 950-1193, 1108-1173 and 1173-1223 K, respectively. Fe phase is not found in the crystallization zone in all runs. This shows that the growth process is controlled by Fe transport rate. Using determined growth conditions, β-FeSi_2 single crystal with a dimension of 22.0 x 3.5 x 1.0mm has been obtained. To our knowledge, this is the largest volume β-FeSi_2 crystal till now.