Calculation of Te distribution along GaSb axis using (1–3) Tiller’s ratio (Eq. (1)) and (4) Eq. (2): (1, 2) V = 5 mm/h, D = 3 × 10-5 and 1 × 10-5 cm2/s, respectively; (3) D = 3 × 10-5 cm2/s for V growth from 0 to 15 mm/h and further drop to 5 mm/h; (4) h first reaches 12 mm, then drops to 2 mm when growth rate exceeds pulling rate.