MOVPE in GaInAsP systems for opto-electronic applications

Abstract

We have studied the capabilities of the growth of quantum well structures in the GaInAsP material system by metalorganic vapor phase epitaxy (MOVPE) for optical applications. In particular we discuss the interfacial structure and the reproducibility of growth for InP/GaInAs, GaInAsP/GaInAs and InP/GaInAsP quantum well structures as well as the controlled n- and p-type doping, which are the most crucial steps in depositing opto-electronic devices based on quantum wells. It is shown by photoluminescence, X-ray diffractometry and absorbtion spectroscopy that the compositional grading at the interfaces does not exceed 2 monolayers and that the interfaces are atomically flat. The presented data strongly indicate a 2-dimensional mode of growth leading to an exact control of the well and barrier widths. In addition extensive study of the Zn doping mechanisms reveals diffusion coefficients of Zn in InP as low as 6.5 x 10 −14 cm 2/s. The capabilities of the developed MOVPE growth process are demonstrated for GaInAs/GaInAsP separate confinement heterostructure lasers with GaInAs well widths of only 4 monolayers. The lasers emit at 1.3 μm at a threshold current density of 0.78 kA/cm 2.