Semiconductors

The optical blueshift saturation behavior of Mg$_{x}$Zn$_{1-x}$O films

C. Xue^a, J. Zhang^a, X. Lu^b, M. Geng^b, T. Huang^b, T. Zhang^a, D. Gu^a, L. Shen^a, L. Wang<sup>a

a</sup> Department of Physics, School of Physical and Mathematical Sciences, Nanjing Tech University, Nanjing, 211816 China
^b School of 2011, Nanjing Tech University, Nanjing, 211816 China

Abstract: A phenomenon of blueshift saturation was observed from cathodoluminescence (CL) spectra of Mg$_{x}$Zn$_{1-x}$O films (0.069 $\le x\le$ 0.8) that were grown by pulsed laser deposition technology. By analyzing the results of composition-dependent X-ray diffraction spectra, scanning electron microscopy images, absorption spectra, and CL spectra, the crystalline structural disorder was determined via Urbach energy value. Furthermore, a competition mechanism between band-filling effect and band tail states was proposed in the composition-dependent CL spectra. This competition is believed to be responsible for the composition-induced blueshift saturation often observed in the disordered alloy semiconductors. The results of this research can provide important reference in energy-band engineering. Keywords: Mg$_{x}$Zn$_{1-x}$O, luminescence, Urbach energy, band tail state.

Keywords: Mg$_{x}$Zn$_{1-x}$O, luminescence, Urbach energy, band tail state.

Received: 16.06.2021
Revised: 16.06.2021
Accepted: 24.06.2021

Language: English

DOI: 10.21883/FTT.2021.10.51476.PSS191

 English version: Physics of the Solid State, 2021, 63:12, 1869–1874