Comprehensive structural and optical analysis of differently oriented Yb-implanted $\beta$-Ga$_2$O$_3$

TL;DR

This paper investigates how different crystal orientations of Yb-implanted $eta$-Ga$_2$O$_3$ affect structural damage and optical properties, revealing orientation-dependent defect formation and luminescence behavior.

Contribution

It provides a comprehensive analysis of structural and optical effects of Yb implantation in variously oriented $eta$-Ga$_2$O$_3$ crystals, highlighting orientation-specific defect and stress characteristics.

Findings

(010)-oriented crystals have fewer extended defects and compressive stress.

Other orientations exhibit tensile stress and more defects.

(010) crystals show lower Yb$^{3+}$ emission, linked to defect-related luminescence enhancement.

Abstract

This study presents investigations of Yb-doped $\beta$-Ga$_2$O$_3$, an ultrawide bandgap semiconductor with potential use in future power and optoelectronic devices operating in high-radiation environments. The research has focused on the problem of structural damage caused by the implantation of Yb-ions into three differently oriented crystals and the optical response of created systems. The (001), (010), and (-201)-oriented $\beta$-Ga$_2$O$_3$ crystals were implanted with three different fluences of 150 keV Yb ions and examined using a variety of experimental techniques: high-resolution X-ray diffraction (HRXRD), Rutherford backscattering spectrometry in channeling mode (RBS/c), Raman and photoluminescence (PL) spectroscopies, to provide comprehensive information about studied systems. Furthermore, the RBS/c studies were supported by Monte Carlo simulations. The results show distinctions between differently oriented crystals. In particular, (010)-oriented crystals are characterized by the lowest concentration of extended defects and the presence of compressive stress. In contrast, samples with the other two orientations exhibit tensile stress and significantly higher levels of extended defects. Interestingly, the PL spectra of (010)-oriented $\beta$-Ga$_2$O$_3$ show the lowest emission from Yb$^{3+}$ ions, suggesting that specific types of extended defects, whose formation is more favorable in the other two orientations than in (010), enhance Yb$^{3+}$ luminescence instead of suppressing it.