▁Me ijo ▁University , ▁where ▁he ▁was ▁an ▁assistant ▁professor . ▁From ▁ 1 9 9 8 ▁to ▁ 2 0 0 2 , ▁He ▁was ▁an ▁associate ▁professor . ▁In ▁ 2 0 0 2 , ▁he ▁became ▁a ▁professor . ▁In ▁ 2 0 1 0 , ▁he ▁moved ▁to ▁the ▁Gr adu ate ▁School ▁of ▁Engineering , ▁N ago ya ▁University , ▁where ▁he ▁is ▁currently ▁a ▁professor . ▁ ▁He ▁joined ▁Professor ▁Is am u ▁Ak as aki ' s ▁group ▁in ▁ 1 9 8 2 ▁as ▁an ▁under grad uate ▁student . ▁Since ▁then , ▁he ▁has ▁been ▁doing ▁research ▁on ▁the ▁growth , ▁character ization ▁and ▁device ▁applications ▁of ▁group ▁III ▁nit ride ▁sem icon duct ors , ▁which ▁are ▁well ▁known ▁as ▁materials ▁used ▁in ▁blue ▁light - em itting ▁di odes ▁today . ▁In ▁ 1 9 8 5 , ▁he ▁developed ▁low - temper ature ▁depos ited ▁buffer ▁layers ▁for ▁the ▁growth ▁of ▁group ▁III ▁nit ride ▁sem icon duct or ▁films ▁on ▁a ▁sa pp hire ▁substr ate , ▁which ▁led ▁to ▁the ▁real ization ▁of ▁group - III - nit ride ▁sem icon duct or ▁based ▁light - em itting ▁di odes ▁and ▁las er ▁di odes . ▁In ▁ 1 9 8 9 , ▁he ▁succeeded ▁in ▁growing ▁p - type ▁Ga N ▁and ▁fabric ating ▁a ▁p - n - j unction - type ▁Ga N - based ▁U V / blue ▁light - em itting ▁di ode ▁for