Universal alignment of transition metal impurity levels in III–V and II–VI compound semiconductors

Abstract

Existence of a universal energy reference level E HO (Hasegawa-Ohno's hybrid orbital energy level) is pointed out for transition metal (TM) deep levels in tetrahedral semiconductors. When viewed from this reference level, each TM energy level E(TM) in major III–V and II–VI compound semiconductor satisfies a simple universal relation of E( TM) = E HO ± ( m + 1 2 ) Δ E with m = 0, 1, 2, --- and the empirical energy separation quantum ΔE = 0.244 eV for II–VI compounds and 0.240 eV for III–V compounds. The so-called vacuum level pinning of TM levels is not generally valid. The band line-up based on the new TM level alignment is in excellent agreement with experiment.