Bias-selected full Red/Green/Blue color sensing and imaging based on inversely stacked radial PINIP junctions

Abstract

Seeking an ultra-compact new architecture or strategy to achieve filter-less Red/Green/Blue (RGB) color sensing is critical for developing a wide range of high-resolution, low-cost and flexible color discrimination and imaging applications. In this work, a new inversely stacked biomimetic radial junction (RJ) PINIP photodetector, comprising of coaxial multilayers of intrinsic and doped hydrogenated amorphous Si (a-Si:H) thin films coated over silicon nanowires (SiNWs), is demonstrated, which can accomplish bias-selected and tunable spectrum responses to the R, G and B color bands, mimicking the response mechanism in human eyes. Compared to the Bayer matrix sensors, the width of a fundamental RJ-PINIP sensing unit is reduced from ∼3 μm to <500 nm, with an absorber i-layer thinned substantially from ∼1 μm to only ∼50 nm, which is particularly important to achieve a faster photo response and suppress the instability issues in a-Si:H absorber. Notably, the 3D RJ-PINIP sensors can now be easily constructed upon flexible aluminum foils (AF) and operate with a convenient two-terminal connection, which is a prerequisite for scalable matrix device implementation. As a prototype demo, the RGB color sensing and reconstruction functionalities are verified in a 125-RGB color imaging with 520*700 pixels, highlighting their unique potential for developing ultra-compact and flexible RGB imaging applications.

3D Radial Junctions for Robust and Flexible Optoelectronics

“…In recent years, flexible and lightweight solar cells/photodetectors with a high PTWR have attracted much attention for their remarkable capabilities in wearable and biomimetic/bio-friendly applications. [22,[150][151][152][153] Recently, X. Sun et al have successfully demonstrated an exceptionally robust a-Si:H RJ solar cell on ultrasoft, ultrathin, and lightweight Al foil, [77] where the discrete and firmly standing SiNWs can act as firmly anchor sites to host the subsequently deposited amorphous thin films, as shown in Figure 11.…”

Color Sensing and Image Reconstruction Using Intelligent Machine Learning Algorithm with PINIP Radial Junction Imager

“…In recent work, we demonstrated a filterless imager based on a symmetric inversely stacked radial junction (RJ) PINIP (here, P, I, and N stand for p-type, intrinsic, and n-type amorphous Si film) photodetector fabricated around silicon nanowires (SiNWs) [19], where different incident wavelengths are absorbed with different penetration depths in stacked PIN junctions (as shown in the inset of Figure 1a). Such a 3D structure can confine light within the nanowire and redistribute the light field into different absorber layers [20], where the inner layer can absorb long wavelengths while the outer layer can absorb short wavelengths.…”