Impact of Al2O3 and HfO2 Gate Dielectrics on Photoresponse of Graphene Channel Field-Effect MWIR Photodetectors with HgCdTe Absorber
摘要
Arrays of field-effect mid-wave infrared (MWIR) photodetectors with an HgCdTe absorber and graphene channel were fabricated for room-temperature operation. The proposed device does not require cryogenic cooling for high detectivity, unlike most of the other MWIR photon photodetectors. The photodetectors showed a peak photocurrent of 254 µA at an excitation with 4 µm ± 40 nm wavelength and 2.05 mW/cm2 incident power density. The detector shows a high signal-to-noise ratio of ~ 200 to ~ 1200 when coupled with a DC subtractor. The use of HfO2 as gate dielectric increases the photocurrent by ~ 15 times compared to Al2O3. The peak specific detectivity (D*) was 2.36 × 1010 Jones when HfO2 was used as the gate dielectric. A notable achievement of our work is obtaining the performance with a high doping density of ~ 4.34 × 1014 cm−3 in HgCdTe.