Spatial confined hot carrier dynamics for beyond unity quantum efficiency detection
Yu Wan, Zhe Cheng, Zhen Wang, Jiapeng Hu, Zhong Fang, Kangmin Leng, Mengchun Qiu, Kuai Yu, Li Wang, Antoni Rogalski, Qijie Wang, Qi Jie Wang, Jianbin Xu, Weida Hu, Qisheng Wang, Qisheng Wang · Nature Communications · 2025
Photon harvesting and conversion in semiconductors hold critical scientific and technological value due to their wide-ranging applications, including optoelectronics, renewable energy, and thermal management. However, the efficiency of optical-to-electrical energy conversion is fundamentally limited by the rapid relaxation of thermalized carriers. Here, we demonstrate a spatial confinement-controlled hot carrier dynamics in a T-shape lead selenide photo-thermoelectric device, which achieves a room temperature external quantum efficiency values exceeding unity. This enhancement arises from spatial confinement-induced local phonon scattering, which suppresses the optical-excited hot carrier relaxation. As a result, the T-shape lead selenide detector achieves a room temperature peak detectivity of 6.3 × 1010 cm Hz1/2 W−1 beyond thermoelectric theoretical limit. This work establishes a transformative pathway for achieving high-efficiency photodetection and energy conversion technologies. Wan et al. report a T-shaped PbSe photothermoelectric detector in which spatial confinement induced local phonon scattering suppresses the hot carrier relaxation, leading to an external quantum efficiency over unity. Focal plane array with 32x32 pixels is fabricated with a non-uniformity of 5.6E-6%.