Engineering and Enhancing the Spectral Response of nipip HIT Photodetectors

Although commercial heterojunction with intrinsic thin layer (HIT) solar cells are predominantly fabricated on n‐type crystalline silicon substrates, fabrication on p‐type crystalline silicon remains attractive owing to its mature fabrication technology, lower production cost, and potential for optoelectronic applications. This work investigates HIT photodetectors fabricated on p‐type crystalline silicon substrates, with a particular focus on tailoring the spectral response and improving external quantum efficiency. By engineering of the front‐side a‐Si:H(i) film through ambient oxidation or partial removal, the photoresponse can be tuned across ultraviolet, visible, and near‐infrared regions. To further improve the EQE, gold nanoparticles were synthesized and deposited on the HIT photodetector. Due to the localized surface plasmon resonance effect, a significant EQE boost was observed. These findings demonstrate practical strategies to tune and increase the spectral response for silicon‐based broadband sensing applications.