2001-053 – Quantum Dash Devices

Background Quantum dot and quantum wire semiconductors structures are of interest for a variety of electronic and optoelectronic device applications. Unfortunately, the conventional approaches to fabricating quantum dot and quantum wire lasers have limited the commercial applications of quantum dots, particularly in the 1.3 to 1.6 μm wavelength range, which is of particular interest for fiber optic communication systems. One potential problem in fabricating quantum dot and quantum wire lasers is deleterious non-radiative interface recombination. Quantum dots and quantum wires have a large surface-to-volume ratio which renders them especially sensitive to interface defects. Additionally, the small fill factor of quantum dot and quantum wire active regions can cause significant current leakage. The drawbacks of conventional quantum dot laser fabrication methods can result in a threshold current that is much greater than the theoretical limit. Additionally, these same drawbacks can make it difficult to form semiconductor active regions capable of lasing over a wide wavelength range. Technology Description Quantum dot active region structures are disclosed. In a preferred embodiment, the distribution in dot size and the sequence of optical transition energy values associated with the quantum confined states of the dots are selected to facilitate forming a continuous optical gain spectrum over an extended wavelength range. In one embodiment, the quantum dots are self-assembled quantum dots with a length-to-width ratio of at least three along the growth plane. In one embodiment, the quantum dots are formed in quantum wells for improved carrier confinement. In other embodiments, the quantum dots are used as the active region in laser devices, including tunable lasers and monolithic multi-wavelength laser arrays. Andrew Roerick aroerick@innovations.unm.edu 505-277-0608