Very-low-temperature molecular beam epitaxial growth of GaP/AlAs heterostructures for distributed Bragg reflector applications

Abstract

High reflectivity and broad bandwidth AlN/GaN distributed Bragg reflectors grown by molecular-beam epitaxyGrowth and characterization of defect-free GaAs/AlAs distributed Bragg reflector mirrors on patterned InP-based heterostructures J.Using very-low-temperature ͑VLT͒ molecular beam epitaxy ͑MBE͒, ͑Ga,P͒/͑Al,As͒ heterostructures were grown for use in a distributed Bragg reflector ͑DBR͒. Through the use of VLT MBE and control of the group-V overpressure, the microstructure can be controlled resulting in either amorphous or polycrystalline material for both materials. Also, the growth rate is highly dependent on the group-V overpressure due to the high sticking coefficients of both As and P at these low growth temperatures. Using lateral oxidation, the amorphous AlAs was converted to its oxide for use in a visible wavelength DBR. Variabilities within layer thickness, especially the amorphous AlAs layers, were investigated to determine their effect on the DBR reflectivities. Different DBR designs were employed resulting in a double passband DBR which is highly reflective at wavelengths of both 550 and 1100 nm.