Electrophysical properties of PIN photodiodes of the 2.2-2.6 μm range based on InGa(Al)As/InP heterostructures with a metamorphic buffer layer

Due to a large number of applications in the near and short-wave IR spectrum and a relatively high detectivity, PIN photodiodes based on epitaxial InGa(Al)As/InP heterostructures are of a great scientific interest. The operational spectral range of such photodetectors is up to 2.6 μm. However, to reach such wavelengths it is necessary to synthesize heterostructures with metamorphic buffer layers. In our study, we investigated the current-voltage and capacitance–voltage characteristics of PIN photodiodes based on InGa(Al)As/InP heterostructures with an original metamorphic buffer layer and an In0.83Ga0.17Asabsorbing layer grown by means of molecular beam epitaxy. The photodiode chips were formed using standard post-growth processing techniques. The diameter of the photosensitive area of the obtained diodes was 140 μm. The dark currents and the shunt resistance were ~ 300 nA and ~ 25 kΩ at the voltage of -10 mV respectively. Therefore, the suggested metamorphic buffer layer effectively eliminates threading dislocations in the active area of the heterostructure. The obtained heterostructures with metamorphic buffer layers can be used to produce IR photodetectors for the spectral range of 2.2-2.6 μm