High resolution X-ray diffraction analysis of p-type strained InGaAs/AlGaAs multiple quantum well structures

摘要

Be-doped InGaAs/AIGaAs multiple quantum well (MQW) structures, grown by solid-source molecular beam epitaxy with different doping concentration in the wells, were investigated by x-ray diffraction and transmission electron microscopy (TEM). Some features have been observed. (1) The MQW mean mismatch increases from 1.176 × 10{sup}(-3) to 1.195 × 10{sup}(-3) and 1.29 × 10{sup}(-3) for the structures with doping concentration of 1 × 10{sup}17 cm{sup}(-3), 1 × 10{sup}18 cm{sup}(-3) and 2 × 10{sup}19 cm{sup}(-3) in the wells, respectively. (2) The period of the MQW also increases with doping density. (3) The intensity of the first order satellite in the rocking curves decreases as the Be concentration is increased, indicating that indium diffusion in the heavily doped wells is likely more significant than that in the lightly doped ones. (4) The full width at half maximum of the zero-order satellite peak becomes widened as doping concentration increases, indicating that high Be-doping in the well likely deteriorates the interfaces of the multiple quantum well stacks. In addition, TEM measurement is conducted and clear pictures on well and barrier layers of the structures are observed. The information obtained is of great value for the design of p-doped quantum well infrared photodetectors.