CdTe/Mg0.46Cd0.54Te double heterostructures with n-type In doping concentrations, varied from 1 × 1016 to 7 × 1018 cm-3, have been grown on InSb substrates using molecular beam epitaxy. Secondary ion mass spectroscopy measurements show strong diffusion of In from the InSb substrate to the CdTe buffer layer, while the In concentration is constant in the CdTe layer between the two Mg0.46Cd0.54Te barrier layers. Capacitance-voltage measurements show that the dopants are 100% ionized for the doping concentration range from 1 × 1016 to 1 × 1018 cm -3. The carrier lifetime decreases with increasing doping concentration (from 0.73 μs for an unintentionally doped sample to 0.74 ns for a 1 × 1018 cm-3 doped sample) due to the decrease of both radiative and nonradiative lifetimes. Decent carrier lifetimes are achieved (∼100 ns) between 1 × 1016 and 1 × 1017 cm-3 doping levels, which is beneficial for developing n-type monocrystalline CdTe solar cells, photodetectors, and other optoelectronic devices. The strongest photoluminescence intensity is observed when the doping concentration is 1 × 1017 cm -3, which corresponds to the highest internal quantum efficiency.
- Carrier lifetime
- Solar cells
- molecular beam epitaxy (MBE)
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering