The ternary alloy heterojunctions In_xGa_(1-x)As/In_xAl_(1-x)As are important materialswhich have been widely used in microwave and photoelectric devices.The alloy hetero-junctions In_xGa_(1-x)As/In_xAl_(1-x)As(x=0.3)have great potential use in high electron mobili-ty transistors(HEMTs),heterostructure insulated-gate FFTs(HIGFETs)and resonant tun-neling diodes(RTDs).When x rises to 0.53,In_xGa_(1-x)As/In_xAl_(1-x)As can be widely used inthe high-speed electronic devices.The valence-band offset(the value of ΔE_v)at The ternary alloy heterojunctions In_xGa_ (1-x) As / In_xAl_ (1-x) As are important materialswhich have been widely used in microwave and electric devices. The alloys hetero-junctions In_xGa_ (1-x) As / In_xAl_ (1-x (X = 0.3) have great potential use in high electron mobili-ty transistors (HEMTs), heterostructure insulated-gate FFTs (HIGFETs) and resonant tun-neling diodes (RTDs) .When x rises to 0.53, In x Ga 1- x) As / In_xAl_ (1-x) As can widely be used in high-speed electronic devices. The valence-band offset (the value of ΔE_v) at