Gain saturation in InP∕GaInP quantum-dot lasers

Abstract

We have measured the gain-current and gain-quasi–Fermi level separation characteristics for InP∕AlGaInP quantum-dot-laser structures. Saturation of the gain-current characteristics is apparent even though photoluminescence excitation spectroscopy measurements indicate that the 2D states are energetically distant from the dot states. The gain is reduced from the maximum value by the distribution of carriers in the excited dot states, the states in smaller dots and the 2D states.

Exploring the wavelength range of InP/AlGaInP QDs and application to dual-state lasing

“…Atomic force microscopy (AFM) measurements of a similar structure in this series of growths revealed a bi-modal distribution of dot sizes [22] and transmission electron microscopy (TEM) has been used to determine the presence of dot-like structures in a series of growths [8]. Although AFM images are useful for identifying the dots and the form of the size distribution, the exact dimensions may not be representative of those dots formed in a complete growth (as with TEM).…”

The effect of strained confinement layers in InP self-assembled quantum dot material

“…Unfortunately, there are a number of processes that cause a rapid increase in threshold current density at elevated temperatures [6] including gain saturation (e.g. [7]). We address this here by the use of strained confinement layers.…”