Interface Engineering-Assisted 3D-Graphene/Germanium Heterojunction for High-Performance Photodetectors

Abstract

Three-dimensional graphene (3D-Gr) with excellent light absorption properties has received enormous interest, but in conventional processes to prepare 3D-Gr, amorphous carbon layers are inevitably introduced as buffer layers that may degrade the performance of graphene-based devices. Herein, 3D-Gr is prepared on germanium (Ge) using two-dimensional graphene (2D-Gr) as the buffer layer. 2D-Gr as the buffer layer facilitates the in situ synthesis of 3D-Gr on Ge by plasma-enhanced chemical vapor deposition (PECVD) by promoting 2D-Gr nucleation and reducing the barrier height. The growth mechanism is investigated and described. The enhanced light absorption as confirmed by theoretical calculation and 3D-Gr/2D-Gr/Ge with a Schottky junction improves the performance of optoelectronic devices without requiring pre-and post-transfer processes. The photodetector constructed with 3D-Gr/2D-Gr/Ge shows an excellent responsivity of 1.7 A W −1 and detectivity 3.42 × 10 14 cm Hz 1/2 W −1 at a wavelength of 1550 nm. This novel hybrid structure that incorporates 3D-and 2D-Gr into Ge-based integrated circuits and photodetectors delivers excellent performance and has large commercial potential.

2D Graphene in Interface Engineering of 3D Graphene‐Based Thermal Management

“…Consequently, the size and quantity of 3D‐Gr increase gradually. [ 20 ] Figure 4d4 shows the corresponding height distribution obtained from the random line cutting of Figure 4c4. These results verify that pregrown 2D‐Gr leads to transformation from 2D to 3D constructions, and no amorphous carbon interfacial layer is seen.…”

High-Performance 3D Vertically Oriented Graphene Photodetector Using a Floating Indium Tin Oxide Channel

“…Despite the excellent device responsivity, light absorption mainly relies on quantum dots instead of graphene, thus limiting the spectral range of photodetection. Another hybrid structure that incorporates VG and two-dimensional graphene-Gr into Ge-based photodetectors delivers an excellent responsivity of 1.7 A W −1 and detectivity 3.42 × 10 14 cm Hz 1/2 W −1 at a wavelength of 1550 nm [ 27 ]. However, the main light absorption layer of the photodetector at 1550 nm is Germanium rather than VG.…”

Mixed‐Dimensional MoS2/Ge Heterostructure Junction Field‐Effect Transistors for Logic Operation and Photodetection

“…[ 1–14 ] Based on the rapid development of 2D material preparation technologies, there appears to be a new interest in heterostructures between atomically thin 2D and 3D semiconductors, which can be fabricated via well‐established microelectronic technologies, combining their respective advantages. Efforts have been made to develop 2D/3D van der Waals heterostructures, [ 15–22 ] including tungsten disulfide/silicon, [ 23 ] molybdenum telluride (MoTe 2 )/silicon, [ 16 ] monolayer molybdenum diselenide/germanium (Ge), [ 15 ] and graphene/Ge. [ 17,24 ] These have realized a wide range of band gaps and improved charge carrier transport properties.…”

“…Efforts have been made to develop 2D/3D van der Waals heterostructures, [ 15–22 ] including tungsten disulfide/silicon, [ 23 ] molybdenum telluride (MoTe 2 )/silicon, [ 16 ] monolayer molybdenum diselenide/germanium (Ge), [ 15 ] and graphene/Ge. [ 17,24 ] These have realized a wide range of band gaps and improved charge carrier transport properties. The 2D/3D heterojunction can also be suitably applied to another important device, the junction field‐effect transistor (JFET), which operates by varying the depletion region of the p–n junction.…”