Revealing unexplored dopants in semiconducting materials

The advancement of transparent electronics, one of the most anticipated technological developments for the future, is currently inhibited by a shortage of high-performance p-type conductors.
In materials, doping is the intentional introduction of impurities into an intrinsic semiconductor for the purpose of modulating its electrical and optical and structural properties. Recent demonstration of tin monoxide as a successful transparent p-type thin-film transistor and the discovery of its potential for  ambipolar doping, suggests that tin monoxide—an environmentally-friendly earth-abundant material—could offer a solution to this challenge. However, only a handful of elements have been investigated as candidate dopants for this material.
Identifying suitable elements for doping requires an enormous amount of experimentation, that involves expensive trial-and-error approaches and can take years before a suitable substitutional element is found. With the aim of accelerating this process and finding a path for successfully enhancing the electronic properties of SnO, an extensive computational search for useful dopant elements was performed using “Piz Daint” at the CSCS. Employing computer simulations researchers at the University of Basel have discovered that substitutional doping with the family of alkali metals provides an as off yet unexplored possibility to increase the concentration of acceptors (i.e. increase p-type conductivity) without being detrimental to the transparency of SnO.
Over ten shallow donors, which, to the best of our knowledge, have not been previously contemplated, were identified in this accelerated discovery thanks to Piz Daint.  The work presents a detailed analysis of the most promising n-/p -type dopants—offering new insights into the design of an ambipolar semiconductor. If synthesized successfully, such a doped ambipolar oxide could open new avenues for many transparent technologies.
Reference: Miglė Graužinytė, Stefan Goedecker, and José A. Flores-Livas. “Towards bipolar tin monoxide: Revealing unexplored dopants”,  Phys. Rev. Materials 2, 104604 – October 2018.