| Research Abstract |
Aiming at high-performance semiconductor lasers and novel photonic devices, we have developed strain-compensated low-dimensional quantum structures with high-quality interfaces and high-density nanostructures.
Accomplishments obtained in this research are as follows:
(1)A RT-CW operation of GaInAsP/InP quantum-wire lasers (23 nm wide, 5 stacked quantum-wires), fabricated by electron beam lithography, CH_4/H_2-reactive ion etching and two-step organometallic vapor-phase-epitaxial growth processes, was realized for the first time. Lifetime measurement of this quantum-wire laser was also carried out at RT-CW condition, and no noticeable performance degradation was observed even after more than 10,000 hours.
(2)GaInAsP/InP strain-compensated 5-stacked compressively strained quantum-wire lasers with the wire width of 14 nm in the period of 80 nm were realized using this fabrication method.
(3)GaInAsP/InP multiple-quantum-wire structures with the wire widths of 18 nm and 27 nm in the period of 8
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0 nm were fabricated by this fabrication method. Size distributions of these quantum-wire structures were measured by scanning electron microscope and the standard deviation was estimated to be less than 10%.
(4)Wire width dependence of the large energy blue shift in GaInAsP/InP partially strain-compensated vertically-stacked multiple-quantum-wire structures is accurately explained for the first time using an 8 band k・p theory without any fitting parameter. It was found that unlike quantum films, the energy-band structures of strained quantum-wires depend on the amount of strain-compensation in barrier regions and on the number of wire layers, in the vertical stack.
(5)By using a lateral quantum confinement effect, a new type of distributed reflector laser, consisting of a wirelike active section and a passive DBR section with quantum-wire structure was realized. A high performance operation with a threshold current of 2.8 mA, differential quantum efficiency of 35%/facet and sub-mode suppression ratio (SMSR) of 55 dB, was obtained under a RT-CW condition. Less
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