Electronic Materials with Wide Band Gap: Recent Developments

TL;DR

This paper reviews the development of wide band gap semiconductor materials, highlighting recent advances in nitrides and oxides for optical and electronic applications, and discusses ongoing challenges in material stability and conductivity.

Contribution

It provides a comprehensive overview of recent developments in wide band gap materials, emphasizing new materials like GaN, AlN, ZnO, and Ga2O3, and addresses current challenges in their application.

Findings

Wide band gap semiconductors enable ultraviolet and blue light emission.

Nitrides like GaN and AlN are key for optical applications.

Oxide semiconductors face challenges in stable p-type conductivity.

Abstract

The development of semiconductor electronics is shortly reviewed, beginning with the development of germanium devices (band gap $E_g=0.66$ eV) after world war II. Quickly a tendency to alternative materials with wider band gap became apparent, starting with silicon ($E_g=1.12$ eV). This improved the signal/noise ratio for classical electronic applications. Both semiconductors have tetrahedral coordination, and by isoelectronic alternative replacement of Ge or Si with carbon or several anions and cations other semiconductors with wider $E_g$ are obtained, that are transparent for visible light and belong to the group of wide band gap semiconductors. Nowadays some nitrides, especially GaN and AlN, are the most important materials for optical emission in the ultraviolet and blue spectral region. Oxide crystals, such as ZnO and $\beta$-Ga$_2$O$_3$, offer similarly good electronic properties but suffer still from significant difficulties in obtaining stable and technically sufficient $p$-type conductivity.