Analysis of the two-dimensional dark currents in quantum well devices

We present approximate analytical expressions for the principal forms of dark current, thermionic emission, and tunneling, which arise within a two-dimensional quantum well photodetector. A simple closed form expression for the two-dimensional thermionic emission current is obtained as well as a numerical result for the tunneling current. Though the dark currents are calculated making use of the usual approximation for the wave function of that for an infinite square well, these expressions are expected to yield reasonable estimates. These formulas can be applied to properly assess the resulting dark currents in photodetectors which utilize quantum well states for either detection or multiplication.