Photodiode with resonant cavity based on InGaAs/InP for 1.9 μm band

The results of the work aiming at development of a RCE photodiode operating at 1.9 mum are described. Detection is based on interband absorption in a thin pseudomorphic InGaAs layer placed inside a resonant cavity which enhances an optical field. The technology of heterostructures grown by MOCVD has been developed. The photodiode structure comprises, between two parallel Bragg mirrors, an InP p-i-n junction with a thin strained InxGa1-xAs (0.65 less than or equal to x less than or equal to 0.8) layer placed inside an undoped region. The bottom Bragg mirror is composed of an In0.53Ga0.47As/InP quarter-wave layer stack, the top mirror is made of Si/SiO2 layers deposited on epitaxial layers by a sputtering method. Good properties of InxGa1-xAs strained layers and good reflectivity spectra of the Bragg mirrors enable us to obtain RCE photodetectors with photoresponse characteristics at wavelengths near 1.9 mum. Photodetectors exhibit very low dark current densities (of the order of 10(-6) A/CM2).