Conduction Band Edge Discontinuity of In_0.52Ga_0.48As/In_0.52(Ga_1-xAl_x)_0.48As(0≦x≦1) Heterostructures

Abstract

In 0.52 Ga 0.48 As/In 0.52 (Ga 1- x Al x ) 0.48 As/In 0.52 Ga 0.48 As potential barrier structures ( x =0.25, 0.5, 0.75, 1), lattice-matched to InP, were grown by MBE using a pulsed molecular beam method. The conduction band edge discontinuity, Δ E c ( x ) between In 0.52 Ga 0.48 As and In 0.52 (Ga 1- x Al x ) 0.48 As, was obtained for the first time by measuring the current-voltage characteristics through the barrier structure as a function of temperature in the range of 77–300 K. It was confirmed that the conduction band edge discontinuity varies linearly with Al composition, x , (Δ E c ( x )=0.53 x (eV) for 0≦ x ≦1) and is proportional to the band gap difference, Δ E g ( x ), (Δ E c ( x )=0.72Δ E g ( x )(eV) for 0≦ x ≦1).