Fluorine doping: A feasible solution to enhancing the conductivity of high-resistance wide bandgap Mg0.51Zn0.49O active components

TL;DR

This study demonstrates that fluorine doping significantly improves the electrical conductivity and device performance of high-resistance Mg0.51Zn0.49O wide bandgap semiconductors, enabling better optoelectronic applications.

Contribution

The paper introduces fluorine doping via RF plasma-assisted molecular beam epitaxy as an effective method to enhance conductivity in high-Mg MgZnO semiconductors, revealing new donor levels and improved device metrics.

Findings

Fluorine acts as an effective donor in Mg0.51Zn0.49O.

Carrier concentration increased to 2.85E17 cm-3.

Photodetector responsivity improved from 0.34 mA/W to 52 mA/W.

Abstract

N-type doping of high-resistance wide bandgap semiconductors, wurtzite high-Mg-content MgxZn1-xO for instance, has always been a fundamental application-motivated research issue. Herein, we report a solution to enhancing the conductivity of high-resistance Mg0.51Zn0.49O active components, which has been reliably achieved by fluorine doping via radio-frequency plasma assisted molecular beam epitaxial growth. Fluorine dopants were demonstrated to be effective donors in Mg0.51Zn0.49O single crystal film having a solar-blind 4.43 eV bandgap, with an average concentration of 1.0E19 F/cm3.The dramatically increased carrier concentration (2.85E17 cm-3 vs ~1014 cm-3) and decreased resistivity (129 ohm.cm vs ~10E6 ohm cm) indicate that the electrical properties of semi-insulating Mg0.51Zn0.49O film can be delicately regulated by F doping. Interestingly, two donor levels (17 meV and 74 meV) associated with F were revealed by temperature-dependent Hall measurements. A Schottky type metal-semiconductor-metal ultraviolet photodetector manifests a remarkably enhanced photocurrent, two orders of magnitude higher than that of the undoped counterpart. The responsivity is greatly enhanced from 0.34 mA/W to 52 mA/W under 10 V bias. The detectivity increases from 1.89E9 cm Hz1/2/W to 3.58eE10 cm Hz1/2/W under 10 V bias at room temperature.These results exhibit F doping serves as a promising pathway for improving the performance of high-Mg-content MgxZn1-xO-based devices.