Study of the carrier capture time: Relevance to laser performance

We present an experimental and theoretical study of the carrier capture time into a semiconductor quantum well. We for the first time observe the predicted oscillations of the phonon emission induced capture time experimentally and found good agreement with theory. Calculations show that not only the LO-phonon emission induced capture time (ph-capture) oscillates as a function of well width, but also the carrier-carrier scattering induced capture time (c-c capture) oscillates by more than an order of magnitude as a function of the active layer design. Moreover, the calculated amount of excess carrier heating also oscillates as a function of quantum well thickness. Recently, it has been shown that the carrier capture time is directly related to the nonlinear gain in a quantum well laser. As a result, the nonlinear gain can be tailored by optimizing the capture efficiency using a proper design of the active layer in a quantum well laser