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The potential of InAs quantum-dot (QD) photodetectors for room-temperature high-speed operation at wavelengths near 1.3 μm is evaluated. Specifically, planar metal-semiconductor-metal structures on GaAs substrates containing one absorption layer of self-assembled InAs QDs embedded in Ga(In)As matrices are fabricated, characterized, and analyzed. Light absorption, optically generated carrier transport, and collection mechanisms are studied. The role of the QD embedding matrix in the lateral transport of the photogenerated carriers is also studied by comparing structures with QDs in GaAs and In 0.15 Ga 0.85 As matrices. Devices show low dark currents in tens of nanoamperes and high light sensitivity when adjusted to QD volumes, whereas external quantum efficiency remains in the range 10 -5 -10 -4 for all fabricated samples. The time response of the fabricated devices is obtained using an excitation …
Publication date: 
22 Apr 2010

Anna Persano, Bahram Nabet, Marc Currie, Annalisa Convertino, Gabriella Leo, Adriano Cola

Biblio References: 
Volume: 57 Issue: 6 Pages: 1237-1242
IEEE Transactions on Electron Devices