GSMBE growth and characterizations of AlInP/InGaAsP strain-compensated multiple-layer heterostructures

We have grown long-period AlInP/InGaAsP strain-compensated multiple-layer heterostructures (SCMLHs) and SCMLHs combined with InAsP/InGaAsP strain-compensated multiple quantum wells (SC-MQWs) by gas source molecular beam epitaxy. Etch pit density (EPD) for both structures are in magnitude of ∼105 cm−2. The increment of EPD with increase of period number is small, indicating low sensitivity of the dislocation density to the increase of period number of SCMLHs. High resolution X-ray diffraction and photoluminescence (PL) characterizations of the two structures demonstrate that crystal quality remains high due to strain compensation. Diffusion and segregation of indium were clearly observed in both InGaAsP and AlInP layers by secondary ion mass spectroscopy. As the thickness of epilayers increases In content increases, while Al decreases. PL for the structure of 20-pair AlInP/InGaAsP SCMLHs+InAsP/InGaAsP SC-MQWs shows strong luminescence and narrow line width. The strain-compensated technique can effectively suppress the formation of misfit dislocations in AlInP/InGaAsP SCMLHs although the thicknesses of epilayers are above the critical thickness of consisting materials, which may render its potential application in optoelectronic devices.