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The effects of bismuth on the performances of InP-based detectors and multiple triangular quantum wells in 2–3 µm band have been investigated. The cut-off wavelength of the InGaAsBi detector is tailored to 2.1 µm by the bismuth incorporation in the absorption layer, but the detector still shows an encouraging dark current due to decreased lattice mismatch to InP substrate. The material quality of the InAs/InGaAs triangular quantum wells has been significantly improved by introducing bismuth as a surfactant during growth. The moderate bismuth reduces the surface roughness, improves the heterostructure interfaces and enhances the photoluminescence intensity obviously, whereas deterioration occurs in the case of excessive bismuth flux. Bismuth shows a promising potential to improve InP-based detector and laser structures both by incorporating into the alloys and acting as a surfactant.

We report room temperature low current density of InP-based AlInAs/InGaAs quantum cascade laser (QCL). For a 7.66-mum QCL, the threshold current density of 1.7 kA/cm2 at 300 K, pulsed output power of 800 mW at 80 K, and continuous-wave (CW) output power of 13 mW at 135 K are achieved. An 8.91-mum QCL comprised 100 stage active region operating up to 320 K in pulsed mode also presented.

InGaAsSb/GaSb detector is very promising for novel applications in long-wavelength range (>2 /spl mu/m). Dark current, composed of surface and volume currents, is a leading source of the electronic noise. Due to a large density of surface states of the InGaAsSb surface, the surface recombination current is the dominant factor in the whole dark current. In this paper, the influence of alkali and neutralized (NH/sub 4/)/sub 2/S passivation on the dark current density of InGaAsSb PIN detector has been studied. A new modified neutralized (NH/sub 4/)/sub 2/S passivation method was proposed. Results show a drastic improvement of the device characteristics was obtained by the modified neutralized (NH/sub 4/)/sub 2/S passivation. In our experiment, the PIN detectors were taken from the same epitaxial wafer and prepared by same fabrication process. In order to compare the effect of different (NH/sub 4/)/sub 2/S passivation solution, the devices were divided into two groups. The results indicate that the sulfur-passivation can remove native oxide and depress surface stats of InGaAsSb effectively.

We report on the growth, characterization and performance of compressively strained In/sub 0.75/Ga/sub 0.25/As/InGaAsP (/spl lambda//sub g/=1.3 /spl mu/m) MQW structures on InP substrates for laser diodes in the 2.0-2.1 /spl mu/m range. These laser wafers were grown by gas source molecular beam epitaxy (GSMBE) for the first time. Both broad area and ridge-waveguide structure lasers have been fabricated and evaluated. The electrical and optical properties of high quality InGaAsP, corresponding to the band wavelength of 1.3 /spl mu/m, have been investigated in detail. The properties of InGaAsP layers have a sensitive dependence on the growth temperature. With the optimization of growth conditions, high quality InGaAsP layers with narrow double-crystal X-ray diffraction rocking curve (DCXRC) and PL FWHM, and high Hall mobility have been obtained. The EL at room temperature of broad-area InGaAs/InGaAsP strained MQW laser structures have shown a peak wavelength of 1.98 /spl mu/m, indicating the precise control of material composition and layer thickness. Pulsed lasing at 77 K has been achieved under an injection current of 70 mA for the ridge waveguide structure of laser diodes and the FWHM of the spectrum is 5.3 nm with peak at 1.816 /spl mu/m.