M. Toivonen

All-solid-source molecular beam epitaxy for growth of III–V compound semiconductors

Abstract All-solid-source molecular beam epitaxy (SS-MBE) is a novel variant of MBE. It allows for toxic-gas-free growth of III–V compound semiconductors, including phosphides. We have examined the quality of SS-MBE-grown phosphorus containing heterostructures and laser diodes. The results discussed in this article show that state-of-the-art quantum well (QW) materials and lasers, covering a wide range of bandgaps from red to infrared, can be prepared by SS-MBE.

Effects of rapid thermal annealing on GaInP/AlGaInP lasers grown by all-solid-source molecular beam epitaxy

We have examined the influence of rapid thermal annealing on the performance characteristics of GaInP/AlGaInP quantum well lasers which were grown by all-solid-source molecular beam epitaxy. It was found that when the laser structures were annealed the threshold current densities of the lasers decreased significantly. This improvement in lasing performance could be associated with the possibility that annealing removed nonradiative recombination centers from the quantum wells. The emission wavelength, differential quantum efficiency, and characteristic temperature were not affected to any remarkable extent, indicating that the interdiffusion of group-III elements did not damage the structures.

State-of-the-art aluminum-free 980-nm laser diodes

InGaAs/GaInAsP/GaInP ridge waveguide 980-nm laser diodes for pumping light into erbium doped fiber amplifiers are reviewed. These lasers have very good performance characteristics. They exhibit kink-free, single mode emission up to a power of 250 mW with a slope efficiency of 0.7 to 0.95 W/A, a thermally limited maximum power of 450-500 mW, and the threshold current density of about 150 A/cm/sup 2/. They are relatively stable against temperature variations. A 100 mW power from a fiber-pigtail module has been demonstrated. These lasers withstand severe thermal rollover tests without showing degradation effects. Preliminary lifetime tests indicate that their mean-time-to-failure (MTTF) may be very long, from several hundred thousand to one million hours, if not limited by sudden failure.

Annealing of the deep recombination center in GaInP/AlGaInP quantum wells grown by solid-source molecular beam epitaxy

Time resolved photoluminescence and deep level transient spectroscopy have been used to monitor the effect of rapid thermal annealing on bulk GaInP and GaInP/AlGaInP quantum wells grown by solid source molecular beam epitaxy similar to those used in 650 nm range lasers. Following rapid thermal annealing at temperatures up to 875 °C, reductions in the concentration of several deep level traps are observed. Correlation of these data with photoluminescent intensity and lifetime measurements indicate that the defect labeled N3, 0.83 eV below the conduction band, is the dominant recombination center. The combination of these two transient spectroscopy measurement techniques is therefore not only able to measure the change in deep level concentration, but also to correlate this change with improved carrier lifetimes and, ultimately, reduced threshold current densities in quantum well lasers. There is also evidence to suggest that this same defect, possibly a phosphorous vacancy or a related complex, plays an im...

Light-emitting diode emitting at 650 nm with 200-MHz small-signal modulation bandwidth

State-of-the-art modulation bandwidths are presented for multiquantum well resonant cavity light emitting diodes (RCLEDs) emitting at 650 nm. 84-/spl mu/m size epoxy coated RCLEDs have a 1.4-mW (CW) output power and a small signal modulation bandwidth of 200 MHz at 40 mA bias. 150-/spl mu/m diameter devices yield 3.25-mW and 150-MHz bandwidth at 70-mA bias. An open eye-diagram at 622 Mb/s achieved for the 84-/spl mu/m device makes it very attractive for SONET OC-12 data communication links.

All solid source molecular beam epitaxy growth of strained‐layer InGaAs/GaInAsP/GaInP quantum well lasers (λ=980 nm)

We report on the growth of 980‐nm strained‐layer InGaAs/GaInAsP/GaInP separated confinement quantum well lasers using all solid source molecular beam epitaxy. Valved cracker cells were employed for both phosphorus and arsenic. Fabricated lasers exhibited excellent performance that is comparable to similar lasers grown by gas source molecular beam epitaxy in our laboratory. A maximum output power of 450 mW and over 250 mW in single mode operation was achieved for ridge waveguide lasers with AR/HR coated facets.

High-performance 980-nm strained-layer GaInAs-GaInAsP-GaInP quantum-well lasers grown by all solid-source molecular-beam epitaxy

High-performance strained-layer GaInAs-GaInAsP-GaInP separate-confinement quantum-well lasers emitting at /spl lambda/=980 nm were grown by all solid-source molecular-beam epitaxy. Valved cracker cells were employed to generate group-V beam fluxes. Fabricated ridge-waveguide lasers exhibited stable, kink-free, single-mode operation up to 260 mW. A maximum output power of 550 mW was achieved. Complete thermal roll-over tests were done tens of times without any sign of degradation for p-side up-mounted lasers. Preliminary lifetime tests for over 4500 h at 150-mW power level indicate that these aluminum-free pump lasers are very reliable sources for pumping light into erbium-doped fiber amplifiers.

Temperature behaviour of resonant cavity light-emitting diodes at 650 nm

Performance characteristics of resonant cavity light-emitting diodes operating at the wavelength of 650 nm have been studied. It has been shown that a variation in device temperature significantly modifies the far-field pattern and thus the fibre coupling efficiency, due to a cavity detuning effect. Temperature dependences of output power and emission wavelength are also studied. Modulation bandwidth of >120 MHz and light power of 2 mW (cw) have been achieved for 84 µm devices driven at a 40 mA current. Accelerated ageing tests for 36 000 device hours indicate no degradation in output power.

High-power 600-nm-range lasers grown by solid-source molecular beam epitaxy

This paper presents the performance characteristics and reliability data of AlGaInP-based VISIBLE laser diodes emitting at the wavelengths from 630 to 670 nm. The lasers are grown by toxic gas free solid source molecular beam epitaxy.

Red lasers grown by all-solid-source molecular beam epitaxy

We have prepared high-power 600 nm spectral band quantum well lasers using all-solid-source molecular beam epitaxy for layer growth. An output power up to 3 W in continuous wave mode has been demonstrated at the nominal wavelength of 670 nm, 2 W at 650 nm and 1 W at 630 nm. The threshold current densities are 350- for nm, 500- for nm and less than for nm. The characteristic temperature of threshold current falls within the range of K at nm and is about 60 K at nm. The slope efficiency is between 0.50 and 0.58 W per facet for uncoated devices of 1 mm in cavity length. Maximum observed wall-plug efficiencies are between 30 and 48% for mirror coated lasers. Preliminary lifetests have been carried out for the 650 and 670 nm lasers suggesting that these lasers will be quite reliable in operation.