Structural, Electronic, and Optical Properties of p-Type Semiconductors Cu2O and ZnRh2O4: A Self-Consistent Hybrid Functional Investigation

Daniel Fritsch

doi:10.3390/electronicmat2040035

Abstract

The p-type semiconductors Cu2O and ZnRh2O4 have been under investigation for potential applications as transparent conducting oxides. Here, we re-evaluate their structural, electronic, and optical properties by means of first-principles calculations employing density functional theory and a recently introduced self-consistent hybrid functional approach. Therein, the predefined fraction α of Hartree–Fock exact exchange is determined self-consistently via the inverse of the dielectric constant ε∞. The structural, electronic, and optical properties will be discussed alongside experimental results, with a focus on possible technological applications.

Highlights

Transparent conducting oxides (TCOs) are one important building block of current technological devices, ranging from various display applications to solar cells
The present work focuses on two identified examples for p-type TCOs, namely cuprous oxide (Cu2 O) and ZnRh2 O4
Cu2 O crystallises in the cubic crystal structure, whereas ZnRh2 O4 crystallises in the so-called normal spinel crystal structure, respectively, similar to ZnFe2 O4 [2], but at variance to NiFe2 O4 and CoFe2 O4 which crystallise in the inverse spinel structure [3]

Summary

Introduction

Transparent conducting oxides (TCOs) are one important building block of current technological devices, ranging from various display applications to solar cells. Subsequent first-principles calculations of the whole spinel series ZnM2 O4 (M = Co, Rh, and Ir) tried to identify their conduction mechanism, i.e., hole or polaron conduction [8,9,10] These first-principles calculations employed a range of (semi)local and hybrid exchange and correlation functionals to investigate the structural, electronic, and optical properties of ZnRh2 O4 , respectively. The recent development of a self-consistent hybrid functional [12] provided the motivation for the current work, namely to re-evaluate the structural, electronic, and optical properties of Cu2 O and ZnRh2 O4 , similar to other crystalline [13,14] and amorphous [15,16].

Theoretical Background

Structural Properties

Electronic and Optical Properties

Summary and Outlook