The use of Atmospheric Pressure Spatial Atomic Layer Deposition (AP-SALD) has gained popularity in the last decade. The success of this technique relies on the possibility to deposit thin films in a fast, vacuum-free, low-cost, low-damage, and high throughput way. In this work, we present ZnO and Aluminium doped ZnO (AZO) films deposited by AP-SALD at low temperature (<220 °C) with high uniformity and conformity. The ZnO films present a high transparency of 80%–90% in the visible range, with a tuneable band-gap, between 3.30 eV and 3.55 eV, controlled by the deposition temperature. The carrier density reaches values greater than 3 × 1019 cm−3, while the electron mobility of the films is as high as 5.5 cm2 V−1 s−1, resulting in an optimum resistivity of 5 × 10−2 Ω cm. By doping ZnO with aluminium, the resistivity decreases down to 5.57 × 10−3 Ω cm, as a result of a significant increase in the carrier density up to 4.25 × 1020 cm−3. The combination of ZnO thin films with p-type cuprous oxide (Cu2O), deposited by aerosol assisted metal organic chemical vapor deposition, allowed the formation of oxide-based pn junctions. The dark I-V characteristic curve confirms a rectifying behaviour, opening the window for the production of all-oxide solar cells completely by chemical vapour deposition methods. We also show the potential of AP-SALD to deposit AZO as a transparent conductive oxide layer for silicon heterojunction solar cells.
Deposition of ZnO based thin films by atmospheric pressure spatial atomic layer deposition for application in solar cells
Viet Huong Nguyen, João Resende, Carmen Jiménez, Jean-Luc Deschanvres, Perrine Carroy, Delfina Muñoz, Daniel Bellet, David Muñoz-Rojas; Deposition of ZnO based thin films by atmospheric pressure spatial atomic layer deposition for application in solar cells. J. Renewable Sustainable Energy 1 March 2017; 9 (2): 021203. https://doi.org/10.1063/1.4979822
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