Effect of potential barrier height on the carrier transport in InGaAs/GaAsP multi-quantum wells and photoelectric properties of laser diode

Abstract

The growth and strain-compensation behaviour of InGaAs/GaAsP multi-quantum wells, which were fabricated by metal–organic chemical vapor deposition, have been studied towards the application of these quantum wells in high-power laser diodes. The effect of the height of the potential barrier on the confined level of carrier transport was studied by incorporating different levels of phosphorus content into the GaAsP barrier. The crystal quality and interface roughness of the InGaAs/GaAsP multi-quantum wells with different phosphorus contents were evaluated by high resolution X-ray diffraction and in situ optical surface reflectivity measurements during the growth. The surface morphology and roughness were characterized by atomic force microscopy, which indicates the variation law of surface roughness, terrace width and uniformity with increasing phosphorus content, owing to strain accumulation. Moreover, the defect generation and structural disorder of the multi-quantum wells were investigated by Raman spectroscopy. The optical properties of the multi-quantum wells were characterized by photoluminescence, which shows that the spectral intensity increases as the phosphorus content increases. The results suggest that more electrons are well bound in InGaAs because of the high potential barrier. Finally, the mechanism of the effect of the height of the potential barrier on laser performance was proposed on the basis of simulation calculations and experimental results.