Electronic properties of the Sn1−xPbxO alloy and band alignment of the SnO/PbO system: a DFT study

Abstract

Tin monoxide (SnO) has attracted attention due to its p-type character and capability of ambipolar conductivity when properly doped, properties that are beneficial for the realization of complementary oxide thin film transistors technology, transparent flexible circuits and optoelectronic applications in general. However, its small fundamental band gap (0.7 eV) limits its applications as a solar energy material, therefore tuning its electronic properties is necessary for optimal performance. In this work, we use density functional theory (DFT) calculations to examine the electronic properties of the Sn1−xPbxO ternary oxide system. Alloying with Pb by element substitution increases the band gap of SnO without inducing defect states in the band gap retaining the anti-bonding character of the valence band maximum which is beneficial for p-type conductivity. We also examine the properties of the SnO/PbO heterojunction system in terms of band alignment and the effect of the most common intrinsic defects. A broken gap band alignment for the SnO/PbO heterojunction is calculated, which can be attractive for energy conversion in solar cells, photocatalysis and hydrogen generation.

Pb/Pb3O4 Metal–Semiconductor Nanocomposite Obtained on 4A Zeolite─Optical and Structural Properties

“…Combining lead (Pb) and lead oxide (Pb 3 O 4 ) in the nanocomposite structure could result in a wider band gap. Other literature reports have observed this effect by doping Pb or PbO with other compounds. − In addition, the core–shell configuration of the nanocomposite implies that the particle is not a pure semiconductor. The Pb core and the small width of the shell can affect the electronic properties.…”

Lone but Not Alone: Precise Positioning of Lone Pairs for the Design of Photocatalytic Architectures

“…SnO 2 is a wide-bandgap (∼3.6 eV) semiconductor, where Sn is fully oxidized to Sn 4+ and the Sn 5s 0 states are present at the conduction band minimum (CBM), more positive than the hydrogen evolution potential, which makes it an inefficient catalyst for photoelectrochemical hydrogen evolution. In contrast, SnO has a narrow indirect bandgap of ∼0.7 eV, where the hybridization of 5s 2 electron lone pairs on Sn 2+ with O 2p leads to the formation of lone-pair-derived midgap states that push the valence band maximum (VBM) more negative than the hydrogen evolution potential. The misalignment of the band edges with the hydrogen evolution potential and the less-than-optimal band gaps render both SnO 2 and SnO unviable for water splitting, as corroborated with experimental studies .…”