Defect annihilation-mediated enhanced activation energy of GaAs0.979N0.021-capped InAs/GaAs quantum dots by H− ion implantation

Publication date: 1 October 2017
Source:Thin Solid Films, Volume 639
Author(s): Mahitosh Biswas, Sandeep Singh, Akshay Balgarkashi, Roshan L. Makkar, Anuj Bhatnagar, N.B.V. Subrahmanyam, Shrikrishna K. Gupta, Pramod Bhagwat, Subhananda Chakrabarti
Self-assembled InAs/GaAs quantum dots capped with GaAs0.979N0.021 quantum well grown on GaAs (001) substrates exhibited emission even beyond 1.5μm at room temperature. A low activation energy of 51meV was found, attributed to the incorporation of N into the capping layer. Rapid thermal annealing sufficiently improved photoluminescence (PL) intensity, but it causes strong blue-shift in the PL spectra due to In/Ga intermixing and N out-diffusion and slightly enhanced activation energy of 58.5meV. Because of the blue-shift and low activation energy, optoelectronic devices, where the design is based on a specific wavelength from the active layer, will automatically result in wavelength-sensitive failure. Implanting H^– ions resulted in a two-fold improvement in the PL intensity without the blue-shift and also exhibited an activation energy of 71meV, attributed to the annihilation of defects via formation of N2H complexes. Thus, implanted samples are recommended for wavelength-sensitive optoelectronic device applications.