Vanadium doped beta-Ga2O3 single crystals: Growth, Optical and Terahertz characterization

TL;DR

This paper reports the growth and comprehensive optical and terahertz characterization of vanadium-doped beta-Ga2O3 single crystals, revealing their high resistivity and strong birefringence suitable for THz optical applications.

Contribution

It introduces a method to grow high-resistivity V-doped beta-Ga2O3 crystals and characterizes their optical and terahertz properties, highlighting their potential for THz devices.

Findings

High electrical resistivity in V-doped crystals compared to undoped

Significant birefringence with Dn of 0.3 at 1 THz

Distinct optical and terahertz transmission properties

Abstract

We report the growth of electrically-resistive vanadium-doped beta-Ga2O3 single crystals via the optical floating zone technique. By carefully controlling the growth parameters V-doped crystals with very high electrical resistivity compared to the usual n-type V-doped beta-Ga2O3 (ne~10^(18)/cm^3) can be synthesized. The optical properties of such high resistive V-doped b-Ga2O3 are significantly different compared to the undoped and n-doped crystals. We study the polarization-dependent Raman spectra, polarization-dependent transmission, temperature-dependent photoluminescence in the optical wavelength range and the THz transmission properties in the 0.2 - 2.6 THz range. The V-doped insulating Ga2O3 crystals show strong birefringence with refractive index contrast Dn of 0.3+-0.02 at 1 THz, suggesting it to be an ideal material for optical applications in the THz region.