Band alignment at the BaCuSeF/ZnTe interface

Abstract

In situ photoemission spectroscopy experiments are used to characterize the interface between ZnTe and the wide band gap p-type semiconductor BaCuSeF. The contact is characterized by a null valence-band offset, a large conduction-band offset, and a chemically graded interface. By applying the transitivity rule for band offset and on the basis of similarities in chemical composition, BaCuSeF contact to chalcogenide photovoltaic absorber materials would be expected to have similar properties. By extension, BaCuChF ͑Ch=S,Se,Te͒ materials are suitable as p-layers in p-i-n double-heterojunction solar cells fabricated with CdTe, Cu͑InGa͒Se 2 , and Cu 2 ZnSnS 4 absorbers.

Origins of Hole Doping and Relevant Optoelectronic Properties of Wide Gap p-Type Semiconductor, LaCuOSe

“…Indeed, applying LaCuOSe:Mg epitaxial thin films as the anode layers in OLEDs has yielded a rather low hole injection barrier (∼0.3 eV). 7 More recently, similar works have extended this strategy to include copper selenide grown at room temperature 8,9 and BaCuFSe 10,11 because their valence band maximum (VBM) structures are similar to that of LaCuOSe and are composed of antibonding states of Cu 3d and Se 4p admixed orbitals. [12][13][14][15][16] Although we demonstrated that LaCuOSe can be applied to optoelectronic devices such as OLEDs 7 and excitonic blue LEDs, 17 the carrier transport/doping mechanism is not completely understood.…”

“…Indeed, applying LaCuOSe:Mg epitaxial thin films as the anode layers in OLEDs has yielded a rather low hole injection barrier (∼0.3 eV) . More recently, similar works have extended this strategy to include copper selenide grown at room temperature , and BaCuFSe , because their valence band maximum (VBM) structures are similar to that of LaCuOSe and are composed of antibonding states of Cu 3d and Se 4p admixed orbitals. − …”

The Role of Photoemission Spectroscopies in Heterojunction Research

“…Zakutayev et al [55] investigated the interface formed by ZnTe and the wide-gap material BaCuSeF. Zakutayev et al [55] investigated the interface formed by ZnTe and the wide-gap material BaCuSeF.…”

Defect physics ofBaCuChF(Ch=S, Se, Te)p-typ

“…3 According to photoelectron spectroscopy measurements, surface oxidation decreases the BaCuChF work function 45 which inhibits ex-situ processing of this material in thin film solar cells. 2,46 The combination of oxidized grain boundaries and anisotropic crystal structure causes a 27 fold decrease in mobility of polycrystalline BaCuTeF thin films compared to the c-axis oriented epitaxial samples. 28 Since the ratio of average to in-plane effective mass is 3, 26 the additional factor of 9 must stem from the difference in the carrier mean free path in This conclusion provides chemical guidance for the design of polycrystalline p-type transparent chalcogenides with mobility of free holes suitable for optoelectronic applications.…”

“…BaCuChF (Ch = S, Se, Te) is a family of p-type transparent conductors 1 suitable for contact applications in thin film solar cells 2 and organic light-emitting devices. 3 These fluorochalcogenides are isostructural 4,5,6 with the oxychalcogenide p-type transparent conductors LnCuOCh (Ln = La, Pr, Nd) 7 and the oxypnictide high-temperature superconductors LaFeOPn (Pn = P, As, Sb) 8 (Fig.…”