Tin Incorporation in AgInSe₂ Thin Films: Influence on Conductivity

Abstract

Bipolarity with enhanced conductivity has been achieved by tin incorporation in AgInSe 2 thin films. Structural and optical characterizations of these films prepared by reactive evaporation indicate that the incorporation neither distorts the tetragonal chalcopyrite structure nor affects the optical band gap of the parent compound. A detailed analysis of the low temperature conductivity of AgInSe 2 (AIS) and tin incorporated AgInSe 2 (AIS:Sn) suggests domination by variable range hopping, grain boundary effect, and thermal activation of carriers in different temperature regimes. The enhanced conductivity in AIS:Sn is attributed to donor and acceptor defect level formation, which has pushed the Fermi levels to ∼9 meV below the conduction band edge in n-type films and ∼3 meV above the valence band edge in p-type films. These improved characteristics of the films are likely to promote their suitability for photovoltaic and thermoelectric power generation applications.

Studies on Photoresponse and LPG sensitivity of transparent Al doped ZnO thin films prepared by thermal evaporation technique

“…The absolute value of room temperature SeebeckCoefficient is found to be ~ 45.7μV/K and ~27.5μV/K for 1.5 at% and 3 at% Al respectively. The comparative lower value of thermopower for 3 at% Al doped sample indicates a better conductivity of these films which thus follows the rule-the lower the thermopower, the higher the conductivity [33] 3.5LPG sensitivity The gas sensitivity for films is reported to be dependent on factors such as operating temperature, concentration of gas, morphology and structural parameters of the films [3]. The principle of gas sensors is based on the variation in resistance of the material on exposure to the gas.…”

“…The Fermi level is calculated using the equation [33] S = ± k/e [(EF/ kT) -(γ/k) + A] ………………………………… (6) where k is the Boltzmann constant, e the electronic charge, EF the Fermi energy, T the temperature in Kelvin, γ the temperature coefficient and A is a constant. From the slope of S versus 1/T graph (Fig.…”

Theoretical Design of the Absorber for Intermediate Band Solar Cells from Group‐IV (Si, Ge, and Sn)‐Doped AgAlSe2

“…On the other side, Ag‐based compounds have the lower valence band position than Cu‐based compounds because of the lower d‐orbital energy and longer bond length. Some Ag‐based compounds, like AgInSe 2 , AgAlTe 2 , AgGaTe 2 , and Ag 2 ZnSnSe 4 , have also been studied as the absorber for the single band gap solar cell. The n‐type conductivity has been reported in these Ag‐based compounds, which make them have the ability to keep the IB half‐filled.…”

“…Some Ag‐based compounds, like AgInSe 2 , AgAlTe 2 , AgGaTe 2 , and Ag 2 ZnSnSe 4 , have also been studied as the absorber for the single band gap solar cell. The n‐type conductivity has been reported in these Ag‐based compounds, which make them have the ability to keep the IB half‐filled. Ag‐based chalcopyrite compound like AgAlSe 2 (2.55 eV) with optimum band gap width should be the suitable candidate for the host of IBSC.…”

Electrical and transport properties of nearly stoichiometric transparent n‐type silver indium oxide thin films

“…: where B = 16 γ 3 /( k B ) in which γ is the inverse of the localisation length, is the density of states at the Fermi level, and k B is the Boltzmann constant. The hopping range R ∼ 1.7 Å and the hopping energy of carriers W ∼ 5.2 meV in VRH are calculated using …”