Determination of band offset in MgO/InP heterostructure by X-ray photoelectron spectroscopy

X-ray photoelectron spectroscopy was used to measure the valence-band offset (ΔEV) of MgO/InP heterostructure. Two sets of core level pairs in the MgO/InP system were used to demonstrate the accuracy of the calculation, the ΔEV value was the same (5.33 ± 0.15 eV) when using the In 3d3/2, Mg 2p pair and In 3d5/2, Mg 2p pair, indicating our calculations are accuracy and reasonable. Taking the band gaps of 7.83 eV for MgO and 1.34 eV for InP into consideration, a type-I band alignment of MgO/InP heterostructure was obtained with conduction band offset (CBO) of 1.16 ± 0.15 eV for two sets of core level pairs, indicating a nested interface band alignment heterostructure was prepared. The accurate determination of the band alignment of MgO/InP has a significant impact on the performance of InP-based devices.