Fabrication of ZnSnP2 thin films by phosphidation

Abstract

a b s t r a c tZnSnP 2 is a promising candidate as a solar absorbing material consisting of earth-abundant and low-toxic elements. In this study, the phosphidation method, where co-sputtered Zn-Sn thin films react with phosphorus gas, was adopted for fabricating ZnSnP 2 thin films. To establish the conditions for producing ZnSnP 2 thin films, we investigated the influence of phosphidation temperature on the product phases, and interpreted the experimental results using chemical potential diagrams of the Zn-Sn-P system. ZnSnP 2 thin films with a single phase were obtained by phosphidation at 500°C under a phosphorus vapor pressure of 10 −2 atm. However, formation of ZnSnP 2 protrusions was observed on the surface of the thin films. Based on the experimental results and the chemical potential diagrams, it is indicated that un-reacted liquid Sn particles reacted with Zn and phosphorus gas to form ZnSnP 2 protrusions in a manner similar to the vapor-Liquid-Solid growth mode.

Fabrication of CdSnP2 Thin Films by Phosphidation for Photovoltaic Application

“…In our previous work on ZnSnP 2 , some protrusions with lengths of a few micrometers were formed on ZnSnP 2 thin films by the so-called VLS (vapor−liquid−solid) growth mode. 28,33 In the present study, such protrusions were not observed in CdSnP 2 thin films fabricated by a similar phosphidation process. It is interesting that CdSnP 2 and ZnSnP 2 showed different morphologies in spite of the similarity in constituent elements and crystal structures.…”

“…The details of the experimental conditions were described in our previous 6 work. 28 We used two phase sample with Sn and Sn4P3 as a phosphorus source and 7 phosphorus gas was transported to the precursor thin films using Ar carrier gas, which 8 was deoxidized by passing through a Ti sponge heated at 900 C. The partial pressure of 9 phosphorus was set at approximately 10 −2 atm by controlling the temperature of two phase 10 sample.…”

“…In our previous work, a different 1 surface morphology was observed in ZnSnP2 thin films fabricated even by a similar 2 phosphidation process. 28 Some ZnSnP2 protrusions with the length of a few m were 3 formed on the ZnSnP2 thin film by so-called VLS (Vapor-Liquid-Solid) growth mode. 28,33 4 It is interesting that CdSnP2 and ZnSnP2 showed different morphologies in spite of the 5 similarity in constituent elements and crystal structures.…”

Structure, composition and photoconductivity analysis of zinc tin phosphide ternary compound nanoparticles synthesized by chemical method

“…Several methods have been explored for the preparation of ZTP in form of crystals and thin films using elemental Zn, Sn and P or in combination of Zn-P and Sn-P compounds as starting materials. They include melt solution growth [4,[13][14][15], flux method [9,10], thermal or electron-beam evaporation [2,11,12,16,17], molecular beam epitaxy [5], liquid phase epitaxy [18], phosphidation of Zn-Sn layers [8,19] and others [20], generally, involving high temperature ([ 600°C) and/or vacuum. In some of these methods, the processes are very tricky due to the complexity in thermodynamic phase formation and a large difference in the vapor pressure between Zn and Sn [21,22].…”

Band offset at the heterojunction interfaces of CdS/ZnSnP2, ZnS/ZnSnP2, and In2S3/ZnSnP2

“…[8][9][10] In addition, a high absorption coefficient of about 10 5 cm À1 in the visible light region has been reported. 11,12 Although ZnSnP 2 thin films have been fabricated using several methods such as co-evaporation, 11,13,14 chemical vapor deposition, 15 liquid phase epitaxy, 16,17 molecular beam epitaxy, [18][19][20] and phosphidation, 21 solar cells based on ZnSnP 2 have not been investigated.…”