UV/IR Dual-Wavelength Photodetector Design Based on ZnO/PMMA/PbSe Nanocomposites

A UV/IR dual-wavelength photodetector based on a ZnO/PMMA/PbSe nanocomposite [PMMA = poly(methyl methacrylate)] for simultaneous detection of 365 nm UV and 4 mu m IR radiation is presented. For UV detection spherical nanoparticles of boron-doped ZnO were synthesized and stabilized using hexamethylenetetramine. The absorption intensity in the UV-vis range is increased upon B doping and discrete Fourier transform calculations confirm the results. Responsivity of the fabricated UV detector is 7.8 AW(-1) and the detector gain is 26.49 at a 365 nm input wavelength. For the synthesis of IR detecting PbSe a new method was worked out, including the stabilization of the particles with thioacetamide. The performance of the PbSe based IR detector turns out to be superior to previously reported PbSe based detectors synthesized by established methods. The responsivity and gain of the detector is 8 AW(-1) and 3.31, respectively for 4 mu m incident wavelength. The sensitivity is 30 for IR detection and overall this sensitivity is excellent for sensing in the mid-IR range. All three "chemical factors," the B-doping, the synthesis conditions for nanoparticles, and the surface modification have contributed to the excellent optoelectronic performance of these new photodetector devices, while the polymethyl methacrylate layer turned out to be very effectively reducing the noise for IR detection.