Quasi-ohmic contact formation assisted by the back contact with Cu2Te nanoparticles@reduced graphene oxide composites for highly efficient CdTe solar cells

High‐Performance Ultraviolet Photodetectors Enabled by van der Waals Schottky Junction Based on TiO2 Nanorod Arrays/Au‐Modulated Ti3C2Tx MXene

“…The WFs of MXene samples before and after contacting with the Au thin‐film substrate are measured by Kelvin probe force microscopy (KPFM), as shown in Figure 2g,h. The WF can be calculated from the contact potential difference ( V CPD ) based on the equation $${V_{{\rm{CPD}}}}\; = \;\frac{{{\Phi _{{\rm{sample}}}} - {\Phi _{{\rm{tip}}}}}}{q}$$, [ 36 ] where Φ sample is the WF of the sample, Φ tip is the WF of the probe, q is the elementary charge, and the reference material is Au (WF of ≈5.1 eV [ 37 ] ). The dark and white arrows in Figure S3a (Supporting Information) represent the V CPDs of the probe with Ti 3 C 2 T x MXene and Si substrate, corresponding to 630 and 665 mV, respectively.…”

“…After adding Ti 3 C 2 T x MXene nanosheets, the rectification ratio rises from 3.11 to 134 (±1 V in Figure S5, Supporting Information). Based on the Shockley equation $$J\;\; = \;J{\rm{o}}[\exp \left( {\frac{{qV}}{{\eta kT}}} \right)\; - \;1]$$, [ 36 ] where V is the applied voltage, k is the Boltzmann constant, T is the Kelvin temperature, J o is the dark saturation current density, and η is the Schottky junction diode ideality factor. The J o and η of FTTA PDs are 4.06 × 10 −3 mA cm −2 and 4.3, respectively, which are significantly reduced compared to those of FTA PDs (4.21 mA cm −2 and 10.3).…”

“…Therefore, low R ct and high R r facilitate charge separation and transfer. [ 36 ] The R r increases from 147 Ω cm 2 (FTA PDs) to 546.4 Ω cm 2 (FTTA PDs). Meanwhile, the R ct decreases from 153 Ω cm 2 (FTA PDs) to 93 Ω cm 2 (FTTA PDs), as listed in Table 1 , indicating that the incorporation of Ti 3 C 2 T x MXene enhances the carrier transport ability and reduces their recombination.…”

“…[18] The WFs of MXene samples before and after contacting with the Au thin-film substrate are measured by Kelvin probe force microscopy (KPFM), as shown in Figure 2g,h. The WF can be calculated from the contact potential difference (V CPD ) based on the equation CPD sample tip V q = Φ −Φ , [36] where Φ sample is the WF of the sample, Φ tip is the WF of the probe, q is the elementary charge, and the reference material is Au (WF of ≈5.1 eV [37] ).…”

“…After adding Ti 3 C 2 T x MXene nanosheets, the rectification ratio rises from 3.11 to 134 (±1 V in Figure S5, Supporting Information). [36] where 4c), rendering the photodetector can operate in a self-driven mode. Further, the J sc and V oc of FTTA PDs exhibit a similar positive proportional relationship with the light density.…”