Origin of the responsivity characteristics of Au/ZnO/MgZnO and Au/MgZnO/ZnO structured ultraviolet photodetectors

Abstract

We report on the ultraviolet photodetectors based on the MgZnO/ZnO and ZnO/MgZnO double-layer films prepared by magnetron sputtering method. The spectral response shows only one responsivity peak in the 1.0 and 1.5 h photodetectors (denoted by the deposition time of one layer of the films) and two peaks in the 0.5 h photodetectors. To our surprise, the Au/MgZnO/ZnO photodetectors have larger responsivity than that of the Au/ZnO/MgZnO ones. A physical mechanism focused on depletion width is given to explain the above results.

Ultraporous Electron‐Depleted ZnO Nanoparticle Networks for Highly Sensitive Portable Visible‐Blind UV Photodetectors

“…Among highly performing materials, zinc oxide is a promising transparent metal oxide with a room temperature bandgap of 3.37 eV that matches well the lower edge of the visible light spectrum . Nano‐ and microstructured ZnO photodetectors have been produced by several methods such as RF magnetron sputtering, sol‐gel, chemical vapor deposition, and pulsed laser deposition demonstrating significant improvement over bulk equivalents. Recently, Ji et al have demonstrated fabrication of flexible devices with up to 1.56 × 10 3 photo‐ ( I UV ) to dark‐current ( I dark ) ratio at a bias of 3 V by epitaxial growth of ZnO films on poly‐ethylene‐terephthalate (PET).…”

Band-modulation of MgZnO/ZnO Metal-semiconductor-metal Photodetectors

“…As compared to the MSM-PDs without the Mg x Zn 1-x O capping layer, the PDs with the Mg x Zn 1-x O/ZnO bi-layer presented higher dark current, photocurrent, and photoresponsivity due to the shielding of ambient oxygen, defect, and surface states passivation by the Mg x Zn 1-x O capping layer [21]. The Au/Mg x Zn 1-x O/ZnO PDs had larger responsivity than Au/ZnO/Mg x Zn 1-x O PDs [22]. By varying the applied bias voltage, the detection wavelength of the Mg x Zn 1-x O/ZnO MSM-PDs could be modulated from a single to a dual wavelength [23].…”

Barrier thickness dependence of MgxZn1−xO/ZnO quantum well (QW) on the performance of a p-NiO/QW/n-ZnO photodiode

“…ZnO-based materials are attractive semiconductors for fabricating ultraviolet (UV) photodetectors, such as p-n, Schottkybarrier, and metal-semiconductor-metal structures, [1][2][3][4][5][6][7][8][9][10][11][12] due to the advantages of wide band gap (3.2 eV), high transparency (>80%) in the visible wavelength region, high exciton binding energy (60 meV), and non-toxicity. 13,14 The addition of a Mg atom in ZnO leads to the formation of Mg x Zn 1Àx O with a band gap tuneable from 3.2 to 7.8 eV.…”