The fabrication of wafer-scale, ultrathin, and highly
sensitive p-CuInSe2/n-Si heterojunction
photodetectors
is demonstrated. CuInSe2 has been extensively utilized
for photovoltaic applications owing to its excellent optoelectronic
properties. Although the wafer-scale CuInSe2 photodetector
fabrication and device-level demonstration are not well explored,
it is of utmost importance to unveil the beneficial aspects of CuInSe2 by fabricating its wafer-scale heterojunction photodetectors.
The wafer-scale CuInSe2 photodetectors are still underway,
and the possible light management mechanism for various CuInSe2 thicknesses is underexplored. As a result, it is demanded
to discover minimum and optimum CuInSe2 thickness for highly
efficient wafer-scale photodetection. To serve this purpose, a strategy
is projected to greatly increase the photodetection performance, possessing
excellent sensitivity, broad spectral responsivity, and stability
along with high speed. Our understanding demonstrates the capability
to control the thickness parameter (from 436 to 43 nm) and alter the
structural, optical, chemical, and optoelectronic characteristics
of the p-CuInSe2 semiconductors in an
unprecedented manner to attain the desired characteristics of photodetection
performance. The maximum sensitivity, detectivity, and LDR, that is,
3.7 × 103, 0.61 × 1011 Jones, and
72 dB, respectively, are obtained under the halogen light for self-biased
conditions. The highly efficient NIR response has been attained, and
maximum sensitivity, responsivity, detectivity, and LDR, that is,
2.2 × 103, 158 A/W, 1.3 × 1012 Jones,
and 79 dB at 980 nm, respectively, are obtained. The present work
offers a sustainable approach for the wafer-scale uniform synthesis
of ultrathin CuInSe2 (58 nm) for the development of self-biased,
highly efficient, and broadband photodetectors.