Photocarrier Escape Time in Quantum-Well Light-Absorbing Devices: Effects of Electric Field and Well Parameters

摘要

We analyze the dependence of the carrier escape time from a single-quantum-well optoelectronic device on the aplied electric field and well width and depth. For this purpose, a new simple and computationally efficient theory is developed. This theory is accurate in the case of electrons, and the assessment of the applicability for holes is given. Semi-analytical expressions for the escape times are derived. Calculations are compared to experimental results and previous numerical simulations. Significant correlations between the position of quantum-well energy levels and the value of the escape time are found. The main escape mechanism at room temperature is established to be thermally assisted tunneling/emission through near-barrier-edge states. The formation of a new eigenstate in the near-barrier-edge energy region is found to reduce the electron escape time significantly, which can be used for practical device optimization.