title: Extraordinary Changes in the Electronic Structure and Properties of CdS and ZnS by Anionic Substitution: Cosubstitution of P and Cl in Place of S.
abstract: Unlike cation substitution, anion substitution in inorganic materials such as metal oxides and sulfides would be expected to bring about major changes in the electronic structure and properties. In order to explore this important aspect, we have carried out first-principles DFT calculations to determine the effects of substitution of P and Cl on the properties of CdS and ZnS in hexagonal and cubic structures and show that a sub-band of the trivalent phosphorus with strong bonding with the cation appears in the gap just above the valence band, causing a reduction in the gap and enhancement of dielectric properties. Experimentally, it has been possible to substitute P and Cl in hexagonal CdS and ZnS. The doping reduces the band gap significantly as predicted by theory. A similar decrease in the band gap is observed in N and F co-substituted in cubic ZnS. Such anionic substitution helps to improve hydrogen evolution from CdS semiconductor structures and may give rise to other applications as well.
authors.affiliation: Theoretical Sciences Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O., Bangalore 560 064 (India).
authors.forename: Summayya
authors.initials: S
authors.lastname: Kouser
authors.affiliation: New Chemistry Unit, CSIR Centre of Excellence in Chemistry, International Centre for Materials Science and Sheikh Saqr Laboratory, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O., Bangalore 560 064 (India).
authors.forename: S R
authors.initials: SR
authors.lastname: Lingampalli
authors.affiliation: New Chemistry Unit, CSIR Centre of Excellence in Chemistry, International Centre for Materials Science and Sheikh Saqr Laboratory, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O., Bangalore 560 064 (India).
authors.forename: P
authors.initials: P
authors.lastname: Chithaiah
authors.affiliation: New Chemistry Unit, CSIR Centre of Excellence in Chemistry, International Centre for Materials Science and Sheikh Saqr Laboratory, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O., Bangalore 560 064 (India).
authors.forename: Anand
authors.initials: A
authors.lastname: Roy
authors.affiliation: New Chemistry Unit, CSIR Centre of Excellence in Chemistry, International Centre for Materials Science and Sheikh Saqr Laboratory, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O., Bangalore 560 064 (India).
authors.forename: Sujoy
authors.initials: S
authors.lastname: Saha
authors.affiliation: Theoretical Sciences Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O., Bangalore 560 064 (India).
authors.forename: Umesh V
authors.initials: UV
authors.lastname: Waghmare
authors.affiliation: New Chemistry Unit, CSIR Centre of Excellence in Chemistry, International Centre for Materials Science and Sheikh Saqr Laboratory, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O., Bangalore 560 064 (India). cnrrao@jncasr.ac.in.
authors.forename: C N R
authors.initials: CN
authors.lastname: Rao
keywords: X-ray photoelectron spectroscopy; co-substitution; electronic structure; photocatalysis; semiconductors