Band Alignment at GaN/Single-Layer WSe₂ Interface

Abstract

We study the band discontinuity at the GaN/single-layer (SL) WSe heterointerface. The GaN thin layer is epitaxially grown by molecular beam epitaxy on chemically vapor deposited SL-WSe/c-sapphire. We confirm that the WSe was formed as an SL from structural and optical analyses using atomic force microscopy, scanning transmission electron microscopy, micro-Raman, absorbance, and microphotoluminescence spectra. The determination of band offset parameters at the GaN/SL-WSe heterojunction is obtained by high-resolution X-ray photoelectron spectroscopy, electron affinities, and the electronic bandgap values of SL-WSe and GaN. The valence band and conduction band offset values are determined to be 2.25 ± 0.15 and 0.80 ± 0.15 eV, respectively, with type II band alignment. The band alignment parameters determined here provide a route toward the integration of group III nitride semiconducting materials with transition metal dichalcogenides (TMDs) for designing and modeling of their heterojunction-based electronic and optoelectronic devices.

Type-I band alignment at MoS2/In0.15Al0.85N lattice matched heterojunction and realization of MoS2 quantum well

“…43 However, our previous reports show the enormous quenching (100-150 times) of PL for nitrogen plasma irradiated MoS 2 layers and 2D/3D heterojunctions. 16,23 In this study, we preserved the PL signal of the QW with relatively high intensity (quenched by 5 times) and a comparable peak width of 70 meV by using the low nitrogen flow rate and low forward power of plasma source for the growth of In 0. 15 The blue shift in PL spectra with respect to the MoS 2 single layer confirmed that the MoS 2 well exhibits the quantum confinement effect.…”

“…Yamada et al reported the growth of GaN on bulk MoS 2 by plasma-enhanced molecular beam epitaxy (MBE). 14 22,23 In spite of the smaller in-plane lattice mismatch (%0.8%) of GaN with MoS 2 , 15 the type-II heterojunction formed by them can be solely utilized for electronic devices. [11][12][13] In contrast, optoelectronic devices formed by 2D/ 3D heterojunctions require a type-I band alignment which can be realized by using the group III-nitride alloys with higher bandgap as a constituent semiconducting layer of the 2D/3D heterojunction.…”

Valence and conduction band offsets of β-Ga2O3/AlN heterojunction

“…The details of the XPS setup have been described in previous studies on different heterojunctions. 30,31 To evaluate the VBO at the b-Ga 2 O 3 /AlN interface, we need to determine the energy difference between the Ga and Al CLs from sample C and also the energy of CLs relative to the respective VBMs of samples A and B. Also, the CLs of Ga 3d and Al 2p were chosen in the analysis.…”

Band alignment of B0.14Al0.86N/Al0.7Ga0.3N heterojunction

“…The core levels (CLs) and valence band photoemission spectra of B 0.14 Al 0.86 N and Al 0.7 Ga 0.3 N films were measured using the HR-XPS method which has been extensively utilized to measure the VBO of a heterointerface. [15][16][17][18] After the MOVPE growth, the samples were stored in the N 2 glove box of our MOVPE system. Due to the wafer transfer and cutting processes prior to the HR-XPS experiment, the samples were exposed to the air for about 20 min, which might have caused surface oxidation.…”