Helicity-dependent terahertz emission from bismuth telluride (Bi₂Te₃) topological insulator grown at different growth temperatures

Topological insulators (TIs) are excellent novel materials for tunable terahertz devices. The topological nature of their surface states leads to helicity-dependent photocurrents that can produce controllable helicity-dependent terahertz sources. However, the underlying optoelectronic properties, particularly the bulk carrier density, can have a significant impact on the THz emission properties. Here, we investigate helicity-dependent THz emission from Bi2Te3 TI materials with varying bulk carrier mobility and carrier concentration at different growth temperatures. Our preliminary investigation shows that the emission mechanisms and underlying photocurrents in TIs is overly sensitive to optoelectronic properties during TI growth. These results offer important insight into optimization of growth temperature and optoelectronic properties to effectively use TI for device applications.