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arXiv · 2405.19110

Barrier height inhomogeneity and origin of 1/f-noise in topological insulator-based photo-detector

Sk Kalimuddin·Biswajit Das·Sudipta Chatterjee·Arnab Bera·Satyabrata Bera·Kalyan Kumar Chattopadhyay·Mintu Mondal
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Abstract

Topological insulators (TIs) with symmetry-protected surface states, offer exciting opportunities for next-generation photonic and optoelectronic device applications. The heterojunctions of TIs and semiconductors (e.g. Si, Ge) have been observed to excellent photo-responsive characteristics. However, the realization of high-frequency operations in these heterojunctions can be hindered by unwanted 1/f (or Flicker) noise and phase noise. Therefore, an in-depth understanding of 1/f noise figures becomes paramount for the effective utilization of such materials.Here we report optoelectronic response and 1/f noise characteristics of a p-n diode fabricated using topological insulator, Bi2Se3 and silicon for potential photo-detector. Through meticulous temperature-dependent current-voltage (I-V) and capacitance-voltage (C-V) measurements, we ascertain crucial parameters like barrier height, ideality factor, and reverse saturation current of the photodetector. The low-frequency 1/f conductance noise spectra suggest a significant presence of trap states influencing the optoelectronic transport properties. The forward noise characteristics exhibit typical 1/f features, having a uni-slope across four decades of frequency, suggesting a homogeneous distribution of barrier height. The spectral and photocurrent-dependent responses show the power law behavior of noise level on photon flux. The hybrid heterojunction demonstrates excellent photo-response and reasonably low noise level, promising signatures for the room-temperature visible photodetector applications.

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Sk Kalimuddin, Biswajit Das, Sudipta Chatterjee, Arnab Bera, Satyabrata Bera, Kalyan Kumar Chattopadhyay, Mintu Mondal. 2024-05-29. Barrier height inhomogeneity and origin of 1/f-noise in topological insulator-based photo-detector. https://doi.org/10.1021/acsami.5c07584

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