Visible spectrum photodetector devices fabricated using molecular crystals of carbon C60 are reported. The devices operate efficiently, extending over and beyond the full visible light spectrum (300–710 nm) with a bias voltage tunable responsivity of 4 mA–0.5 mA W−1. Across this range of wavelengths, the noise equivalent power of these devices remains below 102 nW Hz−1/2, providing a detectivity of 107 Jones. The noise current in these devices is found to have a strong dependence on both bias voltage and frequency, varying by 4 orders of magnitude from 1 nA Hz−1/2 to 0.1 pA Hz−1/2.
The devices also display a near-linear dependence of photocurrent on light intensity over 4 orders of magnitude, providing a dynamic range approaching 80 dB. The 3 dB bandwidth of the devices is found to be above 102 Hz, while the 18 dB bandwidth exceeds 1 kHz. The transient photocurrents of the devices have a rise time of ≈50 µs and a long fall time of ≈4 ms. The spectral photocurrent of the devices is found to quench gradually with a reduction in temperature from ≈300 K and is fully quenched at temperatures below T ≈ 100 K. Upon reheating, the device performance is fully recovered.
Saran, R. and Curry, R.J., 2017. Solution Processable 1D Fullerene C60 Crystals for Visible Spectrum Photodetectors. Small.
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Categories: Photonics & Optoelectronics