Realizing an epitaxial interface between a superconductor (SC) and a topological insulator (TI) is crucial for studying emergent quantum phenomena such as topological superconductivity. So far, this epitaxial heterostructure has been mainly investigated by growing TI films on SC substrates. Here, we reverse the order by epitaxially growing ultrathin films of $\alpha$-Sn, a SC layer, on top of TIs. $In situ$ scanning tunneling microscopy reveals that similar thin films of $\alpha$-Sn (111), from monolayer to quintuple layer, can be realized on a wide range of substrates from n-type ${\mathrm{Bi}}_2{\mathrm{Te}}_3$ to p-type ${\mathrm{Sb}}_2{\mathrm{Te}}_3$. We obtain superconductivity with a transition temperature around 1 K from these heterostructures across the n-type to p-type crossover. The large spin-orbit coupling of our systems can give rise to enhanced in-plane upper critical magnetic field. Our work reveals the potential of employing the $\alpha \text{−}\text{Sn/}(\text{Bi},{\mathrm{Sb})}_2{\mathrm{Te}}_3$ heterostructures for transport studies on emergent phenomena due to nontrivial topology.

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• Superconductors
• Topological insulators
• Transport phenomena
• Thin films
• Molecular beam epitaxy
• Scanning tunneling microscopy
• X-ray diffraction