This hole-trapping process significantly separates
the electron–hole pairs and largely increases the carrier lifetime. [3, 4, 47] Meanwhile, the superior crystallinity of InSb nanowires can reduce the scattering and carrier trapping during the transport process between two electrodes, and the photocurrent rapidly reaches a steady state in both the response and the recovery stages . XAV-939 datasheet Additionally, the electron mobility may affect t tran and enhance the QE.  Because t tran = l/v and v = μE (where l is the electrode distance) the carrier drift velocity v is the product of mobility μ and the applied electric field, while the QE can be rewritten as QE = τ/t tran = τμE/l. In this work, the mobility value of the InSb nanowire is 215.25 cm2 V−1 s−1, which
guarantees the effective transport of the electrons between two electrodes. Finally, the M-S-M structure with back-to-back Schottky contacts can significantly enhance the photocurrent density and further increase the sensitivity of the device. The enhancement is caused by the enhanced surface band-banding effect due to the existence of the localized Schottky contact, leading to a pronounced electron–hole separation effect. Figure 5a illustrates the band diagrams of the Schottky barrier with a Repotrectinib cost reverse bias in the dark. The depletion region (λ) near the InSb CBL0137 nanowire surface is formed by the surface state in the contacted region between the depletion region and the Pt electrode. In the dark, the width of the depletion region is thick, which hinders the carrier flow and, therefore, reduces the dark current. Under illumination, the photogenerated electrons and holes are attracted to lower energy sites, subsequently leading to transporting the electrons and the holes along two paths. Moreover, the separation of electrons and holes further reduces the recombination Carnitine dehydrogenase probability and significantly increases the lifetime. The holes are mostly trapped in the depletion region under a reverse bias. The redistribution of the space charge increases the positive charge density in the depletion region,
thereby shrinking its width. The narrowing of the depletion region allows the electrons to tunnel in the nanowire. Contemporarily, the accumulated positive charge attracts electrons from the electrode into the nanowire, resulting in the enhancement of a current gain greater than unity and increasing the electron transport speed [49, 50], as shown in Figure 5b. Furthermore, the oxygen is desorbed and reabsorbed in the interfacial region rather than over the entire surface of the nanowire. Therefore, the response and recovery time significantly decrease . Figure 5 Band diagrams of metal–semiconductor-metal structure. (a) Dark conditions under bias V b and (b) under illumination with bias V b. Φ 1 and Φ 2 are the Schottky barriers at the two ends. λ is the depletion width.