Te-doped GaSb single crystals have great application potential in infrared detectors owing to their high mobilities. Therefore, improving the room-temperature mobility is crucial to suppressing device dark current and enhancing detector response speed. However, most of the previous studies focus only on the impurity compensation effect of Te doping while ignoring its critical regulation on carrier transport mechanisms. In this study, ${\mathrm{GaSb}}_{1-x}{\mathrm{Te}}_x$ single crystals ($0\le x\le 3.48\%$) were grown via the flux method. The crystal with $x=137\mathrm{ppm}$ achieves an exceptional room-temperature electron mobility of $4273{\mathrm{cm}}^2{\mathrm{V}}^{-1}{\mathrm{s}}^{-1}$, exceeding previously reported values. Systematic transport measurements reveal two successive doping-driven transitions: a carrier-type conversion from $p$-type to $n$-type at $x=137\mathrm{ppm}$, followed by a transition from nondegenerate semiconducting behavior to degenerate metalliclike behavior at $x=0.29\%$. The evolution of carrier characteristics and mobility stems from the complex interplay between impurity compensation, ionized impurity scattering, and phonon scattering mechanisms. Electrical transport and spectroscopic analyses demonstrate that Te doping induces a shift of the Fermi level into the conduction band. Furthermore, the distinct Shubnikov-de Haas oscillations directly confirm the establishment of degenerate behavior. These results clarify the dual role of Te in impurity compensation and band structure modulation, while providing key insights for designing high-quality infrared detectors via precise doping.

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• Carrier dynamics
• Optoelectronics
• Quantum transport
• III-V semiconductors
• Photodetectors
• Single crystal materials
• Crystal growth
• Shubnikov-de Haas effect