Investigation of energy band at atomic layer deposited AZO/β-Ga2O3 ($$ \overline{2}01 $$) heterojunctions

Abstract

The Al-doped effects on the band offsets of ZnO/β-Ga 2 O 3 interfaces are characterized by X-ray photoelectron spectroscopy and calculated by first-principle simulations. The conduction band offsets vary from 1.39 to 1.67 eV, the valence band offsets reduce from 0.06 to − 0.42 eV, exhibiting an almost linear dependence with respect to the Al doping ratio varying from 0 to 10%. Consequently, a type-I band alignment forms at the interface of ZnO/β-Ga 2 O 3 heterojunction and the AZO/β-Ga 2 O 3 interface has a type-II band alignment. This is because incorporating Al into the ZnO would open up the band gaps due to the strong Al and O electron mixing, and the conduction and valence band edges consequently shift toward the lower level.

Transport Mechanism of Enhanced Performance in an Amorphous/Monoclinic Mixed-Phase Ga2O3 Solar-Blind Deep Ultraviolet Photodetector

“…Obviously, the charge transfers mainly occurred between the contact parts, which could lead to an effective separation of light generated carriers in this polarization field. The difference in charge indicates the charge transfer direction from the crystalline Ga 2 O 3 to the amorphous Ga 2 O 3 [67]. The results show that the electrostatic intervention can make the amorphous phase negatively charged, while the crystal phase is positively charged.…”

“…Obviously, the charge transfers mainly occurred between the contact parts, which could lead to an effective separation of light generated carriers in this polarization field. The difference in charge indicates the charge transfer direction from the crystalline Ga2O3 to the amorphous Ga2O3 [67]. The difference in charge density perpendicular to the interface was explored, so as to understand the charge transfer and charge distribution between crystalline and amorphous phase Ga 2 O 3 after the interface was formed.…”

Microstructure Evolution and Electrical Behaviors for High-Performance Cu2O/Zr-Doped β-Ga2O3 Heterojunction Diodes

“…However, doping Ga 2 O 3 with an appropriate Zr concentration can effectively diminish recombination losses and attenuate tunneling at the heterojunction interface. Figure e illustrates the energy band alignment of the Cu 2 O, Ga 2 O 3 , and AZO semiconductors, integrating electron affinities and band gaps referenced from the existing literature. − For D 0 , the presence of the CuO phase at the Cu 2 O/Ga 2 O 3 interface results in a significant increase in carrier recombination. This is linked to the amphoteric behavior and narrow band gap of CuO, culminating in Fermi level pinning and predisposing the interface toward an Ohmic behavior, detrimental to the performance of heterojunction diodes. , Furthermore, amorphous Ga 2 O 3 presents various defect states, including self-trapped exciton (STE) states, donor states generated by V O , and acceptor sites stemming from Ga vacancy complexes (V Ga ) and V O –V Ga . , These defects are pivotal in trapping carriers, increasing series resistance, and facilitating carrier tunneling, resulting in recombination at the interface.…”

Toward controlling the Al2O3/ZnO interface properties by in situ ALD preparation

“…29 The interface of ZnO with Ga 2 O 3 has been investigated recently. 17,30 The absence of p-type Ga 2 O 3 , like for most TCOs, has initiated studies of n-type heterostructures with different band gaps. These could serve as an alternative means to study the independent manipulation of carrier injection or carrier confinement.…”