Gate-tunable spectral photoresponsivity of MoS₂-WSe₂ heterojunctions

Miniaturized computational spectrometers provide a path to integrating spectrometers into small scale, on-chip devices. One promising device architecture incorporates a van der Waals heterostructure as the light sensor. The heterostructure exhibits an electrically tunable spectral response which can be paired with a spectral reconstruction algorithm to determine optical spectra in the bandwidth 400 - 750 nm [1]. To optimize this reconstruction algorithm, a strong understanding of the heterojunction photoresponse is necessary. We are building heterojunctions of WSe₂ and MoS₂ and characterizing the electrically tunable spectral response via spectrally resolved photocurrent measurements. We are testing (a) the linearity of the photoresponse with respect to illumination power and (b) the linearity of photocurrent superposition when multiple narrow-band light sources illuminate the heterojunction. Our measurements will be used to improve spectral reconstruction algorithms and will probe the microscopic mechanisms governing the optoelectronic properties of van der Waals heterostructures.



[1] H. H. Yoon et al., Miniaturized Spectrometers with a Tunable van Der Waals Junction, Science 378, 296 (2022).