H. Yanagisawa

Effect of cap layer and cooling atmosphere on the hole concentration of p(Zn)-AlGaInP grown by organometallic vapor phase epitaxy

Abstract Hole concentration of p(Zn)-(Al 0.7 Ga 0.3 ) 0.5 In 0.5 P grown by organometallic vapor phase epitaxy is influenced by cooling atmospheres and capping layers. A high hole concentration is obtained when an epitaxial layer is cooled in a hydrogen stream, while cooling in a phosphine- or arsine-containing hydrogen atmosphere reduces hole concentration in this order. A cap layer, n- or p-GaAs is useful in maintaining a high hole concentration. The zinc acceptors in a layer with a low hole concentration can quickly be reactivated by annealing in hydrogen.

Uniform p‐type impurity‐doped multiquantum well AlGaInP semiconductor lasers with a lasing wavelength of 633 nm at 20 °C

Impurity doping into a GaInP/AlGaInP multiquantum well (MQW) active layer is applied to suppress the occurrence of the ordered structure of column III elements. Calculation of the quantized energy level in an ordered and disordered GaInP quantum well (QW) shows that uniform p‐type impurity doping into a MQW structure is more effective than modulation doping for shortening the lasing wavelength. The lasing wavelength of p‐doped MQW lasers with a 3‐nm‐thick GaInP QW can be shortened to 633.2 nm at an output power of 2 mW at 20 °C. A maximum lasing temperature of 46 °C for a 630 nm band AlGaInP MQW laser with a cavity length of 450 μm is obtained.

Study on strain-induced polarization mode of strained-layer quantum-well 630-nm AlGaInP LD's

Low-threshold operation of 630-nm AlGaInP LDs is examined by introducing compressive and tensile strains into quantum wells (QWs), and the dependence of threshold currents on the effects of strain is investigated. We also try to determine the correlation between the strain-induced polarization mode and threshold currents so as to optimize the strained QW structure for low threshold operation. Experimental results reveal a good correlation when the same device parameters are used. Based on that correlation, applying the larger strain and the QW-structure design that enhances the main polarization mode is effective in obtaining a low threshold. Opposite dependences of the relative intensity of the polarization mode on such device parameters as cavity length and facet reflectivity are observed under the two types of strain. Under tensile strain, the polarization-mode intensity increases as the mirror loss increases and the device temperature rises.<<ETX>>

Characterization of GaInP layers grown on GaAs substrates monitored by surface photo-absorption

In situ monitoring by surface photo-absorption (SPA) was used in metalorganic vapor phase epitaxy (MOVPE) growth of Ga 0.5 In 0.5 P ternary alloy semiconductor for the first time. Two modes were employed to supply the group III precursors: the alternate supply and the simultaneous supply. Monolayer-wise growths per supply cycle are possible for both growth modes. X-ray diffraction measurement and transmission electron microscopy (TEM) observation show that lattice mismatch of GaInP epitaxial layers can be controlled when a simultaneous supply is employed. Photoluminescene (PL) was measured for single GaInP layers and GaInP/AlGaInP double hetero (DH) structures grown at various temperatures. The results show that the PL intensity greatly depends on the growth temperature

High-power highly reliable operation (40 mW at 60/spl deg/C) of compressively strained quantum-well 680-nm AlGaInP LDs

Optimized thin quantum-well (QW) structures under compressive strain are examined for high-power characteristics suitable for light sources of optical disk systems. As a result, compressively strained triple-quantum-well LDs can operate stably at 40 mW and a high temperature of 60/spl deg/C for over 1000 hours.

Low-threshold strained-layer quantum-well 630-nm AlGaInP LDs and relative intensity of strain-induced polarization mode

Summary form only given. Low-threshold CW operation of 630-nm AlGaInP LDs with compressive- or tensile-strained quantum-well structures is investigated. In addition, the correlation between the threshold current and polarization-mode intensity is discussed in terms of strain effects and injected carrier density.

Optimization of MQW structure in 630 nm AlGaInP laser diodes for high-temperature operation

In recent years there has been intensive study on shortening the lasing wavelength of AlGaInP laser diodes by introducing a quaternary active layerl or a ternary quantum well (QW) structure. CW operation at the lasing wavelength of 633 nm, which corresponds to that of a He-Ne gas laser, has been attained by adopting a multiquantum well (MQW) structure with very thin QWs. However, the performance at high temperatures was not good enough to allow an operating temperature higher than 50/spl deg/C. This is thought to be caused by significant carrier overflow from the active layer, which tends to increase with shorter lasing wavelength as the bandgap difference between the active layer and the cladding layers becomes smaller. We first evaluate the effect of the number of QWs on the carrier confinement and the high-temperature characteristics, and then use the results to optimize the structure of an MQW made on misoriented substrates.