Cubic (Rocksalt) Semiconductors: Fundamentals and Applications

Since 1950's progress in the information technology era have been primarily orchestrated by semiconductors, which has fundamentally changed our society. While Si has remained as the most important semiconducting material for integrated chip industry, last few decades have also seen the emergence of compound semiconductors such as GaN, GaAs and others for optoelectronic applications. However, both the Si and other commonly used compound semiconductors exhibit non-cubic (non-rocksalt) crystal structure, which makes atomic scale arrangement of such materials with metals (that typically exhibit cubic crystal structure) extraordinarily difficult. Such mis-matches in the crystal structure between semiconductors and metals significantly limits various types of device performance.

Heterogeneous Integration Research Group (HIRG) researches on cubic (rocksalt) semiconductors such as Scandium Nitride (ScN) and its alloy with other wurtzite III-nitride semiconductors such as AlN, GaN and InN. The group is developing these novel materials with a variety of methods including MBE and magnetron sputtering, and their physical properties are addressed in greater details. Similarly, the group have also interest in other cubic nitride semiconductors such as YN, CrN and rare-earth mono-nitrides.

Publication

1. B. Saha, M. Garbrecht, J. Andres, Y. R. Koh, L. Hultman, M. M. Gonzalez, A. Shakouri and T. D. Sands, "Compensation of Native Donor Doping in ScN: Carrier Concentration Control and p-type ScN", Appl. Phys. Lett. 110, 252104 (2017).

2. B. Saha, S. Saber, E. Stach, E. P. Kvam, and T. D. Sands "Understanding the Rocksalt to Wurtzite Phase Transformation Through Microstructural Analysis of (Al,Sc)N Epitaxial Thin Films. Appl. Phys. Lett. 109, 172102 (2016).

3. Y. Chen, S. Zhang, W. Gao, F. Ke, J. Yan, B. Saha, C. Ko, J. Suh, B. Chen, J. W. Ager III, W. Walukiewicz, R. Jeanloz, J. Wu, "Pressure-induced structural transition and phase diagram of CdxZn1-xO alloys", Appl. Phys. Lett. 108, 152105 (2016).

4. B. Saha, S. Saber, G. V. Naik, A. Boltasseva, E. Stach, E. P. Kvam, and T. D. Sands, "Development of epitaxial AlxSc1-xN for artificially structured metal/semiconductor superlattice metamaterials." Phys. Stat. Sol. B, 252, 251 (2015). (Editor's Choice and Cover Article, Purdue MSE News)

5. B. Saha, G. Naik, V. Drachev, A. Boltasseva, E. E. Marinero, and T. D. Sands, "Electrical and optical properties of ScN and Mn-doped ScN deposited by dc-magnetron sputtering." J. Appl. Phys., 114, 063519 (2013).

6. P. V. Burmistrova, J. Maassen, T. Favaloro, B. Saha, S. Salamat, Y. R. Koh, M. S. Lundstrom, A. Shakouri, and T. D. Sands, "High mobility and high thermoelectric power factor in epitaxial ScN films deposited by reactive magnetron sputtering onto MgO(001) substrate." J. Appl. Phys. 113, 153704 (2013).

7. B. Saha, T. D. Sands and U. V. Waghmare, "Electronic structure, vibrational spectrum, and thermal properties of yttrium nitride (YN): A first-principles study." J. Appl. Phys. 109, 083717 (2011).

8. B. Saha, J. Acharya, T. D. Sands and U. V. Waghmare, "Electronic structures, phonons and thermal properties of ScN, ZrN and HfN: A first-principles Study", J. Appl. Phys. 107, 033715 (2010).