This book is devoted to the physics and technology of diode lasers based on self-organized quantum dots (QD). It addresses the fundamental and technology aspects of QD edge-emitting and vertical-cavity surface-emitting lasers, reviewing their current status and future prospects. The theoretically predicted advantages of an ideal QD array for laser applications are discussed and the basic principles of QD formation using self-organization phenomena are reviewed. Structural and optical properties of self-organized QDs are considered with a number of examples in different material systems. The book includes recent achievements in controlling the QD properties such as the effect of vertical stacking, changing the matrix bandgap and the surface density of QDs. The book is also focused on the use of self-organized quantum dots in laser structures, fabrication and characterization of edge- and surface-emitting diode lasers, their properties and optimization. Special attention is paid to the relationship between structural and electronic properties of QDs and laser characteristics. The threshold and power characteristics of the state-of-the-art QD lasers are also demonstrated. Issues related to the long-wavelength (1.3-um) lasers on a GaAs substrate are also addressed and recent results on InGaAsN-based diode lasers presented for the purpose of comparison.

No abstract

No abstract

An InAs quantum dot (QD) array covered by a thin InGaAs layer was used as the active region of diode lasers grown by molecular beam epitaxy on GaAs substrates. The wavelength of the ground-state transition in such heterostructures is in the 1.3 μm range. In the laser based on the single layer of QDs, lasing proceeds via the excited states due to insufficient gain of the ground level. Stacking of three QD planes prevents gain saturation and results in a low threshold (85 A/cm2 in broad-area 1.9-mm-long stripe) long-wavelength (1.25 μm) lasing at room temperature via the QD ground state with relatively high differential efficiency (>50%).