Tuning of hole carrier density in p-type α-SnWO₄ by exploiting oxygen defects

Abstract

The development of p-type oxide semiconductors has shown promise in overcoming limitations restricting the practical usage of oxide semiconductors and the realization of innovative functional devices. Through numerous studies based...

Recent progress in the development of tin tungstate (α-SnWO4) photoanodes for solar water oxidation

“…Minohara et al fabricated a p-type α-SnWO 4 by controlling the annealing temperature or the concentration of oxygen defects. 44,45 α-SnWO 4 samples with n-type conductivity, however, are more common. Several density functional theory (DFT) calculations have been performed to understand the electronic structure of α-SnWO 4 .…”

Band Gap Narrowing by Suppressed Lone-Pair Activity of Bi3+

“…Semiconductors containing post-transition metal cations with a lone pair ( n s 2 n p 0 ) electronic configuration (Sn 2+ , Sb 3+ , Pb 2+ , Bi 3+ ) are a special class of photoabsorbers in solar-to-energy conversion systems. − The filled s orbitals interact with anion orbitals to form the upper valence band, providing unique optoelectronic properties such as defect tolerance, reduced hole effective mass, , and shallow ionization potentials. These effects have led to promising photo­(electro)­catalysts such as BiVO 4 , , Bi 4 NbO 8 Cl, , and Pb 2 Ti 2 O 5.4 F 1.2 …”

Destabilization of Sn2+ 5s2 Lone-Pair States of SnO through Dimensional Crossover

“…The generation of electrons by the formation of interstitial oxygen was also reported in α-SnWO 4 . 18 However, the source of electrons is still an open question because the interstitial oxygen is not an electrically active defect on the basis of theory. 51,52 Finding v suggested that the O 2p z and Sn 5s,5p hybridization states forming the lone pair were destabilized in the thin SnO films.…”

“…Via application of these functionalities, high-efficiency perovskite solar cells, lead-free ferroelectrics, and p-type oxide semiconductors and photocatalysts for water splitting have been designed and developed. − The development of p-type oxide semiconductors with a wide bandgap is essential for realizing innovative electronic devices for ultralow power consumption in transparent , and high-power , electronics. Recently, state-of-the-art p-type oxide semiconductors have been developed on the basis of the lone-pair states of Sn 2+ or Bi 3+ . − The optical bandgap was manipulated by transforming the chemical composition from infrared to ultraviolet. , Furthermore, hole densities of Sn 2+ - or Bi 3+ -based complex oxides were controlled over several orders of magnitude using precise defect control or intentional chemical doping. , …”

“…12,15 Furthermore, hole densities of Sn 2+or Bi 3+ -based complex oxides were controlled over several orders of magnitude using precise defect control or intentional chemical doping. 18,19 However, practical applications are still hindered by several issues. One is the low hole generation efficiency.…”