Computationally guided control of carriers in complex Diamond-like semiconductors for thermoelectric
Channel: Biblioteca Pós-graduação em Física UFMG
Date: 2022-06-30

Título: Computationally guided control of carriers in complex Diamond-like semiconductors for thermoelectric applications

Palestrante: Lídia Carvalho - Universidade de Illinois em Urbana-Champaign, EUA

Resumo:

The increasing predictive power of first-principles calculations has been of extreme importance in the identification and characterization of defects in diverse materials. An example are the recent advances in the ability to control the charge carriers in thermoelectrics, which must be dopable to a significant degree for good performance.

This presentation will review our recent computational efforts to understand and tailor defect chemistry and dopability of a chemically-diverse set of telluride-based diamond-like semiconductors (DLS), the ternaries IBIIITe2 with IB=(Cu,Ag), III=(In,Ga), of interest for their potential as thermoelectrics. DLS compounds are typically observed to be p-type, but a materials' descriptor suggests that they would be more effective as thermoelectrics if they could be doped n-type.

First-principles methods are then used to predict the achievable range of carrier concentrations using calculations of phase stability, defect formation energies, and carrier concentrations. Within the investigated set of materials, enhancing n-type behavior requires a delicate competition between intrinsic defects. Using this observation as a design strategy, we identify candidate diamond-like semiconductors that may be more amenable to n-type doping. Finally, I will discuss how such predictions can be used to guide synthesis conditions to achieve specific carriers type and concentrations using the phase boundary mapping experimental technique.