Optical TCAD on the Net: A tight-binding study of inter-band light transitions in self-assembled InAs/GaAs quantum dot photodetectors

Abstract

A new capability of our well-known NEMO 3-D simulator (Ref. Klimeck et al., 2007 [10]) is introduced by carefully investigating the utility of III-V semiconductor quantum dots as infrared photodetectors at a wavelength of 1.2-1.5 mu m. We not only present a detailed description of the simulation methodology coupled to the atomistic sp(3)d(5)s* tight-binding band model, but also validate the suggested methodology with a focus on a proof of principle on small GaAs quantum dots (QDs). Then, we move the simulation scope to optical properties of realistically sized dome-shaped InAs/GaAs QDs that are grown by self-assembly and typically contain a few million atoms. Performing numerical experiments with a variation in QD size, we not only show that the strength of ground state inter-band light transitions can be optimized via QD size-engineering, but also find that the hole ground state wavefunction serves as a control factor of transition strengths. Finally, we briefly introduce the web-based cyber infrastructure that is developed as a government-funded project to support online education and research via TCAD simulations. This work not only serves as a useful guideline to experimentalists for potential device designs and other modelers for the self-development of optical TCAD, but also provides a good chance to learn about the science gateway project ongoing in the Republic of Korea. (C) 2012 Elsevier Ltd. All rights reserved.

Keywords

Optoelectronics; Tight-binding; Atomistic modeling; III-V photodetector; Parallel computing; Science gateway; ELECTRONIC-STRUCTURE; NEMO 3-D; SCIENCE; ATOM; SIMULATIONS; PARAMETERS; GATEWAYS; GAAS

DOI

10.1016/j.mcm.2012.11.024

Date of this Version

7-2013

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