We report measurements on transport perpendicular to a single quantum well located on thenside of ap‐njunction in a InP/InGaAs device. Zero‐bias admittance spectroscopy and photocapacitance transient measurements are used to characterize electron and hole emission rates. Both rates show a crossover from a thermally activated regime to a regime of weak temperature dependence. The barrier dimensions for electron and hole emission preclude direct tunneling so that, in the low‐temperature regime, transport must be defect assisted. In this regime we observe discrete fluctuations in the reverse‐bias photocapacitance and photocurrent and in the forward‐bias dark current. The results are explained with a model in which transport of electrons in or out of the well is regulated by the occupancy of a single electron trap associated with a defect.