STUDY OF Al0.065Ga0.935Sb AVALANCHE PHOTODETECTORS FOR 1.55 μm OF WAVELENGTH BY LIQUID PHASE EPITAXY AT LOW TEMPERATURE

Abstract

We report the results of a study of Al 0.065 Ga 0.935 Sb avalanche photodetectors grown on n-GaSb substrates. The devices have been fabricated from layers with the structure p-Al 0.13 Ga 0.87 Sb/n-Al 0.065 Ga 0.935 Sb:Te/n-GaSb (substrate) grown by liquid phase epitaxy (LPE) with a composition matched to detect light of 1.55 μm. The heterostructures were grown from Ga-rich solutions at 400°C. Just after their growth, the structures were subjected to baking processes inside the growth chamber. The baking time was varied and its influence on the breakdown voltages of the junctions was observed. Breakdown voltages up to 12 V, very low net donor concentration in the active layer (1E15 cm -3), and avalanche multiplication factors of around 50 have been obtained. The carrier concentration was determined by the C–V method. Photoluminescence and X-ray diffraction measurements were carried out to investigate the properties of the LPE-grown ternary layers, to determine the band gap and to estimate the quality of epitaxial layers. The photoresponses of the detectors are also presented.