Determining the band alignment of copper-oxide gallium-oxide heterostructures

Abstract

The copper oxides cuprite (Cu2O) and tenorite (CuO) are ideal candidates for solar cells as they promise high conversion efficiencies according to the Shockley–Queisser limit. However, both cannot readily be doped n-type, thus hampering the formation of all copper oxide p–n junctions for solar cell applications. The combination of the copper oxides with gallium sesquioxide, in particular, α-Ga2O3 and β-Ga2O3, is considered to be an excellent heterojunction system for overcoming this challenge. In such a p–n junction, the p-type copper oxide layer will act as an absorber and the transparent n-type gallium sesquioxide will act as a window layer. In these devices, the band alignment at the internal interface is crucial for the device performance. Here, we study the band alignments of four different copper oxide–gallium sesquioxide heterostructures by x-ray photoelectron spectroscopy. Within the experimental margin of error, a Cu2O/α-Ga2O3 heterostructure appears to offer the most favorable band alignment for photovoltaic applications.

Investigation of high-performance Schottky diodes on a Ga2O3 epilayer using Cu with high barrier height, high temperature stability and repeatability

“…In figure 6, the XRD peaks corresponding to the Cu(I) oxide (Cu 2 O) and Cu(II) oxide (CuO) phases of copper oxide are clearly observed. All these XRD peaks of copper oxide formation were matched with reported data and Joint Committee on Powder Diffraction Standards(JCPDS) file numbers: #782076, #895899, #770199, #801917, and #895897 [53,54]. Here, G(001), G(002), G(003), and G(004) are the XRD peaks of the Ga 2 O 3 (001) epilayer.…”

Heterojunction Devices Fabricated from Sprayed n-Type Ga2O3, Combined with Sputtered p-Type NiO and Cu2O

“…They found that α-Ga 2 O 3 /Cu 2 O has the lowest CBO of ~0.2 eV and a VBO of ~3.2 eV, while, in β-Ga 2 O 3 /Cu 2 O junctions, the CBO increases to ~1.3 eV and the VBO to ~3.7 eV. To this respect, they claimed that the use of α-Ga 2 O 3 bears the highest potential for application in solar cells in combination with Cu 2 O [21]. Their work, however, did not show electrical characterization of the junctions.…”

Facile fabrication and enhanced photoresponse of CuO/β-Ga2O3 nanostructure photodetector

“…With the development of technology, people use different synthesis methods to integrate two different metal oxide semiconductor materials to form different structures in order to improve their photoelectric properties. For example, ZnO/Ga 2 O 3 and CuO/Ga 2 O 3 heterostructure UV photodetectors have been reported [19][20][21]. However, the facile fabrication of CuO/β-Ga 2 O 3 nano-heterojunctions and their effects on response performance remains underdeveloped.…”