EU PVSEC Programme Online
EU PVSEC 2021, 6 - 10 September 2021
Presentation: 3BO.10.5 Approaching Theoretical Band Gap of ZnSnN2 Films via Bias Magnetron Co-Sputtering at Room Temperature
Type: Oral
Date: Tuesday, 7th September 2021
17:00 - 18:30
Author(s): A. Virfeu, F.M. Alnjiman, A. Borroto, J. Ghanbaja, C. Longeaud, S. Le Gall, L. Kopprio, J.-P. Vilcot, J.F. Pierson
Presenter / Speaker: A. Virfeu, University of Lorraine, Nancy, France
Event: Conference Conference
Session: 3BO.10 III-V Solar Cells and Related Compounds
Topic: 3. 4 III-V and Related Compound Semiconductors
Summary / Abstract: IV-II-N2semiconductors are promising optoelectronicbehavior and good candidates for thin film photovoltaic absorbers materials. The Zn-IV-N2type compounds would cover a large part of the solar spectrum for bandgap energies ranging from 1.4 eV (ZnSnN2) to 5.7 eV (ZnSiN2)1. The structure of these compounds is closely related to the III-N semiconductor ones with III= Al, Ga, In, which are thermodynamically stable, and where the element of column III is replaced by a sublatticeof zinc cations and atoms of column IV (Si, Ge, Sn)2. Due to their tunable band gap and the choice of earth-abundant and non-toxic elements, they may replace InxGa1-xN alloys materials, which became expensive because of the depletion of the mining resources3.Few years ago, studies from Atwater’s group showed that a large composition of alloys can be grown without phase separation1. Although, theoretical predictions estimate an optical band gap in the order of 1.4eV, the practical use of this system has been limited because of the difficulty to reach expected value4. In other nitrides such as InN, high free carrier densities due to unintentional oxygen incorporation led to degenerate carrier doping and an overestimation of the bandgap by more than 1 eV due to the Burstein–Moss shift5. Recently, few works investigate the disorder caused by unintentional oxygen incorporation and the grains boundaries oxygen contamination in ZnSnN2thin films6,7. To reduce oxygen contamination and improve physico-chemical properties, a new approach is investigated by the use of bias during film growth.It is well-known that the properties of films is governed by the processing parameters as pressure, temperature, and bias voltage among others. A negative bias voltage applied to the substrate can significantly improve the ionization and energy of the sputtered particles and enhancing the film crystallization by increasing the grain size8.