SEMICONDUCTOR THEORY
Journal of Semiconductors, Volume. 40, Issue 3, 030202(2019)
Direct or indirect band gap
SEMICONDUCTOR THEORY
Direct or indirect band gap
Phys. Rev. B,
The direct or indirect nature to the bandgap of a semiconductor is a fundamental property. Despite the extensive research and broad applications of the conventional semiconductors, the understanding of the mechanisms determining their direct or indirect nature to the bandgap remains a challenge. Lack of fundamental understanding of the mechanism controlling the indirect bandgap nature of Si might be the main reason for the difficulty of developing Si-based direct bandgap materials.
Yuan et al. resolved this long-standing puzzle by presenting a unified theory for understanding the direct or indirect nature of bandgap in conventional group II−VI, group III−V, and group IV semiconductors unambiguously. They found that the occupied cation d bands play a prime role in forming the direct or indirect bandgap of semiconductors via the s−d and p−d coupling with the states of the X- and L-valley, which remarkably pushes their energy levels up, but leaves the Γ-valley intact. The either lacking or low-lying of the occupied d orbitals in cations of Diamond, Si, Ge, and Al-containing group III−V semiconductors explains their nature of indirect bandgap.
Junyi Zhu (The Chinese University of Hong Kong, Hong Kong, China)
doi: 10.1088/1674-4926/40/3/030202
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. Direct or indirect band gap[J]. Journal of Semiconductors, 2019, 40(3): 030202
Category: Research Highlight
Received: --
Accepted: --
Published Online: Sep. 18, 2021
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