TY - JOUR
T1 - VxIn(2-x)S3 Intermediate Band Absorbers Deposited by Atomic Layer Deposition
AU - McCarthy, Robert F.
AU - Weimer, Matthew S.
AU - Haasch, Richard T.
AU - Schaller, Richard D.
AU - Hock, Adam S.
AU - Martinson, Alex B.F.
PY - 2016/4/26
Y1 - 2016/4/26
N2 - Substitutional alloys of several thin film semiconductors have been proposed as intermediate band (IB) materials for use in next-generation photovoltaics, which aim to utilize a larger fraction of the solar spectrum without sacrificing significant photovoltage. We demonstrate a novel approach to IB material growth, namely atomic layer deposition (ALD), to allow unique control over substitutional-dopant location and density. Two new ALD processes for vanadium sulfide incorporation are introduced, one of which incorporates a vanadium(III) amidinate previously untested for ALD. Using this process, we synthesize the first thin film VxIn(2-x)S3 intermediate band semiconductors and further demonstrate that the V:In ratio, and therefore intraband gap density of states, can be finely tuned according to the ALD dosing schedule. Deposition on a crystalline In2S3 underlayer promotes the growth of a tetragonal β-In2S3-like phase VxIn(2-x)S3, which exhibits a distinct sub-band gap absorption peak with onset near 1.1 eV in agreement with computational predictions. However, the VxIn(2-x)S3 films lack the lower-energy transition predicted for a partially filled IB, and photoelectrochemical devices reveal a photocurrent response only from illumination with energy sufficient to span the parent band gap.
AB - Substitutional alloys of several thin film semiconductors have been proposed as intermediate band (IB) materials for use in next-generation photovoltaics, which aim to utilize a larger fraction of the solar spectrum without sacrificing significant photovoltage. We demonstrate a novel approach to IB material growth, namely atomic layer deposition (ALD), to allow unique control over substitutional-dopant location and density. Two new ALD processes for vanadium sulfide incorporation are introduced, one of which incorporates a vanadium(III) amidinate previously untested for ALD. Using this process, we synthesize the first thin film VxIn(2-x)S3 intermediate band semiconductors and further demonstrate that the V:In ratio, and therefore intraband gap density of states, can be finely tuned according to the ALD dosing schedule. Deposition on a crystalline In2S3 underlayer promotes the growth of a tetragonal β-In2S3-like phase VxIn(2-x)S3, which exhibits a distinct sub-band gap absorption peak with onset near 1.1 eV in agreement with computational predictions. However, the VxIn(2-x)S3 films lack the lower-energy transition predicted for a partially filled IB, and photoelectrochemical devices reveal a photocurrent response only from illumination with energy sufficient to span the parent band gap.
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U2 - 10.1021/acs.chemmater.5b04402
DO - 10.1021/acs.chemmater.5b04402
M3 - Article
AN - SCOPUS:84964780429
VL - 28
SP - 2033
EP - 2040
JO - Chemistry of Materials
JF - Chemistry of Materials
SN - 0897-4756
IS - 7
ER -