The Investigation of Carrier Mobility Effect on the Performance Characteristics of the InGaN-Based Vertical Cavity Surface Emitting Laser (VCSEL) by Solving the Rate Equations

Abstract

Among the parameters that play an important role in describing the performance of many devices is carrier mobility which is a criterion for the easy movement in semiconductor crystals. The effect of carrier mobility on the performance characteristics of InGaN quantum well vertical cavity surface-emitting laser was analytically investigated. By solving the Poisson’s equation, current density equation, charge concentration continuity equation and carrier and photon rate equations, the variation of current density and carrier density with respect to the position and time and the effects of carrier mobility and temperature on these parameters were investigated. Furthermore, the effect of mobility on the variation of output power versus the injection current and on the time variation of photon and carrier density and output power was investigated. By increasing the carrier mobility, the threshold current reduced and the output power increased. In studying the effect of temperature on the desired parameters, the variation of carrier density with respect to time and position was affected by the temperature change. This phenomenon is due to the dependence of these parameters on the diffusion coefficients and consequently on the mobility of the carriers and the dependence of mobility on temperature. The threshold current was reduced when the electron mobility rises due to the increased accumulation of carriers and consequently the increase of carrier recombination. The output power increased, and the time delay to accrue the laser decreased. Consequently, the carrier recombination increased, further resulting in a rapid laser operation.