High sensitivity of photodetection via fermion to boson condensation

Abstract Boson exhibits neutral charge property and negligible contribution to electrical transport. Therefore, it is very significant to enhance the electrical performance of optoelectronics. However, it is difficult to utilize the bosonic behaviors in photodetection due to its fermionic quantum statistical distribution, which is quite different to that of bosons. Herein, we realize a high sensitivity of photodetection via fermion to boson condensation in layered titanium selenide (TiSe2) under rapid and slow cooling procedures. The bosonic condensation, revealed by creative combination of the temperature-dependent electromagnetic induced well (EIW) effect and the resistance of TiSe2, obviously not only decreases the fermionic carrier concentration but also improves its mobility. The noise equivalent power NEP in terahertz waveband based on EIW effect is 35.45 fW·Hz-1/2, 4.53 fW·Hz-1/2 and 2.25 fW·Hz-1/2 at 0.252 THz, 0.14 THz and 0.027 THz, respectively, which shows one order of magnitude enhancement attributed to the excellent performance increase of electrical transport after bosonic condensation. Moreover, the detectivity D* in visible and infrared bands based on photoconductive effect has threefold improvement compared to no bosonic condensation. Our results provide an approach to realize low noise transport from fermion to boson condensation and pave a way for extremely sensitive photodetection in broad bands.