An arsenic related defect at the In0.53Ga0.47As/oxide interface is studied through density functional theory. This defect corresponds to an As-As timer which transforms into two doubly occupied As dangling bonds upon capture of two electrons. The defect charge transition level is found to be resonant with the bottom of the In0.53Ga0.47As conduction band and weakly sensitive to its local chemical environment. Hence, this defect is a possible candidate for the observed defect density in the conduction band of In0.53Ga0.47As. (C) 2015 Elsevier B.V. All rights reserved.