Writing Research Software in a Large Group for the NEMO Project

The nanoelectronic modeling (NEMO) program is the result of a three-yeardevelopment effort involving four universities and the former Corporate Researchand Development Laboratory of Texas Instruments, now Applied Research Laboratory,Raytheon TI Systems, to create a comprehensive quantum device modeling toolfor layered semiconductor structures. Based on the non-equilibrium Green functionformalism, it includes the effects of quantum charging, bandstructure and incoherentscattering from alloy disorder, interface roughness, acoustic phonons, and polar opticalphonons. NEMO addresses the diverse needs of two different types of users: (i) theengineer/experimentalist who desires a black-box design tool and (ii) the theorist who isinterested in a detailed investigation of the physics. A collection of models trade offphysical content with speed and memory requirements. Access to this comprehensivetheoretical framework is accommodated by a Graphical User Interface (GUI) thatfacilitates device prototyping and in situ data analysis. We describe a hierarchicalsoftware design that allows rapid incorporation of theory enhancements whilemaintaining a user-friendly GUI, thus satisfying the conflicting criteria of ease of useand ease of development. The theory and GUI modules share data structures that definethe device structure, material parameters, and simulation parameters. These datastructures may contain general data such as integer and real numbers, option lists,vectors, matrices and the labels for both batch and GUI operation. NEMO generatesthe corresponding GUI elements at run-time for display and entry of these datastructures