Effect of doping on the characteristics of infrared photodetectors based on van der Waals heterostructures with multiple graphene layers

Abstract

Keywords: graphene, van der Waals heterostructure, infrared photodetector. We study the operation of infrared photodetectors based on van der Waals heterostructures with the multiple graphene layers (GLs) and n-type emitter and collector contacts. The operation of such GL infrared photodetectors (GLIPs) is associated with the photoassisted escape of electrons from the GLs into the continuum states in the conduction band of the barrier layers due to the interband photon absorption, the propagation of these electrons and the electrons injected from the emitter across the heterostructure and their collection by the collector contact. The space charge of the holes trapped in the GLs provides a relatively strong injection and large photoelectric gain. We calculate the GLIP responsivity and dark current detectivity as functions of the energy of incident infrared photons and the structural parameters. It is shown that both the periodic selective doping of the inter-GL barrier layers and the GL doping lead to a pronounced variation of the GLIP spectral characteristics, particularly near the interband absorption threshold, while the doping of GLs solely results in a substantial increase in the GLIP detectivity. The doping "engineering" opens wide opportunities for the optimization of GLIPs for operation in different parts of radiation spectrum from near infrared to terahertz.

Vertical Hot-electron Terahertz Detectors Based on Black-As1?xPx/graphene/black-As1?yPy Heterostructures

“…The detectors using this mechanism can exhibit a fairly high performance. (21,22) However, the efficiency of such detectors is limited by the range of sufficiently high photon energies (for example, the detectors based on hBN/G/hBN heterostructures) except for relatively small Δ C values. In this regard, the b-As 1−x P x /G/b-As 1−y P y heterostructure appears to be suitable not only for the detectors using the bolometric effect (at moderate THz frequencies), but also for those using the electron interband photoexcitation (in the range ℏΩ ~100 meV, i.e., Ω/2π ~25 THz).…”

Negative photoconductivity and hot-carrier bolometric detection of terahertz radiation in graphene-phosphorene hybrid structures

“…The values of the GP-detector responsivity demonstrated in Fig. 3 are of the same order of magnitude or can exceed the room temperature responsivity of the proposed and realized THz photodetectors based on different heterostructures [21,[48][49][50][51][52][53][54][55][56][57][58][59], including those based on the P-channel [7,60,61] (although in G-based devices at very low temperatures much higher responsivities have been achieved [20]).…”

Interband infrared photodetectors based on HgTe–CdHgTe quantum-well heterostructures

“…In the opposite case, the electron escape from the QWs is associated with the tunneling through the triangular barrier formed by the electric field. Using a simplified model for the characteristics of the vertical photodetectors using the photoexcitation from the localized states in the structure and the electron injection from the emitter (used previously in the papers on the standard QWIPs as well as in the GLIPs [19][20][21][22][23][24][25][26][27]), one can obtain for the photocurrent density in the QWIP j photo and its photodetector responsivity R = j photo /I ω ω…”

“…Due to the features of the energy spectrum in the QWs, these interband QWIPs can operate at the normal IR radiation incidence. In this regard, the interband HgTe-CdHgTe QWIP operation is akin to the operation of the vertical graphene-layer infrared photodetectors (GLIPs) [25][26][27].…”