STRAIN EFFECT ON 630 NM GAINP ALGAINP MULTIQUANTUM-WELL LASERS/

We theoretically analyzed the GaInP/AlGaInP strain effect of compressi ve- and tensile-strained multi-quantum well (MQW) lasers with the lasi ng wavelength of 630 nm and under a fixed optical confinement conditio n. Since the compressive-strained MQW has the weaker valence subband m ixing, it can greatly reduce the hole band density of states, and resu lts in the reduction of the threshold current. On the contrary, the te nsile strain increases the density of states, so the strain of up to 0 .5% has no eff ect in reducing the threshold current despite the large matrix element. In the comparison with the experimental results, howe ver, the threshold current density of the compressive-strained MQW obt ained in our calculation is much lower than that in the experimental r esults. It seems that the nonradiative recombination current, which is not included in our calculation, increases in the compressive-straine d MQW because of its narrow well width.