Elemental Tellurium gained particular attention in recent years due to its properties as high mobility, p-type semiconductor and strong infrared light absorber. Its van der Waals structure allows the combination with silicon as well as with two-dimensional materials giving rise to stacked structures with novel electronic and optical properties. Here we report a method to enhance photodetector performances, in terms of photocurrent and response speed at visible and infrared wavelengths, of Te/n-Si heterojunctions by introducing a topological insulator buffer layer of Bi2Se3 between Te and n-Si substrate. The photocurrent of the obtained stacked structure Te/Bi2Se3/n-Si results respectively 2.7 and 59 times higher than that shown by Bi2Se3/n-Si and Te/n-Si at λ = 1550 nm when operating in self-powered mode. Moreover, the response time at visible wavelength decreases up to 6 times with respect to Te/n-Si and 2.9 times to Bi2Se3/n-Si. The obtained results are ascribed to the presence of the high mobility surface states of Bi2Se3 topological insulator. The research confirms the success in combining different nanomaterials for wide range wavelength optoelectronic devices and in the use of topological insulators for fast photodetectors.
Enhanced photoresponse in Te/Bi2Se3/n-Si heterojunctions at visible and telecommunication wavelengths
Crivellari, Michele;
2027-01-01
Abstract
Elemental Tellurium gained particular attention in recent years due to its properties as high mobility, p-type semiconductor and strong infrared light absorber. Its van der Waals structure allows the combination with silicon as well as with two-dimensional materials giving rise to stacked structures with novel electronic and optical properties. Here we report a method to enhance photodetector performances, in terms of photocurrent and response speed at visible and infrared wavelengths, of Te/n-Si heterojunctions by introducing a topological insulator buffer layer of Bi2Se3 between Te and n-Si substrate. The photocurrent of the obtained stacked structure Te/Bi2Se3/n-Si results respectively 2.7 and 59 times higher than that shown by Bi2Se3/n-Si and Te/n-Si at λ = 1550 nm when operating in self-powered mode. Moreover, the response time at visible wavelength decreases up to 6 times with respect to Te/n-Si and 2.9 times to Bi2Se3/n-Si. The obtained results are ascribed to the presence of the high mobility surface states of Bi2Se3 topological insulator. The research confirms the success in combining different nanomaterials for wide range wavelength optoelectronic devices and in the use of topological insulators for fast photodetectors.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
