Highly responsive broadband photodetection in topological insulator - Carbon nanotubes based heterostructure

Highlights:• Novel optical device based on Topological Insulator - Carbon Nanotubes hybrid for broadband photodetection was developed.• Efficient light absorption and electron-hole pair generation observed under illumination of visible and NIR laser light.• Excellent photodetection properties with high photoresponsivity and photoconductive gain was demonstrated by the hybrid. -- Abstract: Topological insulators represent a new electronic phase which comes from the topological character of the bulk wave functions in some special materials. These exotic phases can be attributed to the strong spin-orbit interaction and can be explained with the band theory of solids. Recent studies show that topological insulators (TIs) such as Bi₂Te₃ or Bi₂Se₃ have promising candidature for optoelectronic industry and some of these interesting properties have been already demonstrated such as strong light absorption, photocurrent sensitivity to the polarization of light, layer thickness and size dependent tuning in the band gap. Theoretically, it has been proposed that TIs based broad spectral photodetector has potential in analogy with that of a graphene based photodetector. Combining TIs with carbon-based nanomaterials provides novel and promising technique for photodetection, and can show broad spectral properties. Along this line, we have grown photodetector based on hybrid of TIs with carbon nanotubes. Efficient light absorption and electron hole pair generation has been observed under the illumination of visible (532 nm) and NIR (1064 nm) light. High photoresponsivity and photoconductive gain of 79.4 AW^-1 and 185, respectively, along with very good detector response time were observed in our device under visible laser (532 nm) illumination.