Polycrystalline Zn₃P₂/Indium-Tin Oxide Solar Cells

Abstract

Zinc phosphide (Zn3P2)/indium-tin oxide (ITO) heterojunction solar cells are fabricated by rf sputter depositing ITO on large grain polycrystalline Zn3P2 wafers. An AES analysis indicates that sputter etching of the Zn3P2 wafer surface before depositing ITO is of great importance in achieving a better performance as a solar cell. The passivation of Zn3P2 by reaction with atomic hydrogen is found to improve the cell performance significantly. Consequently, a power conversion efficiency of 2.1% (6 mm2 in active area) has been obtained without antireflection coating.

Unravelling the early oxidation mechanism of zinc phosphide (Zn3P2) surfaces by adsorbed oxygen and water: a first-principles DFT-D3 investigation

“…Despite its germane optoelectronic properties, to date, a Zn 3 P 2 device of sufficient efficiency for commercial applications has not been demonstrated. [11][12][13][14][15][16] Besides problems such as poor band-alignment with buffer layers and inadequate interface passivation, 17,18 low surface stability and oxidation in the presence of oxygen [18][19][20] and moisture 21 remain major problems that severely limit the fabrication of efficient Zn 3 P 2 -based photovoltaics. Zn 3 P 2 typically reacts with moisture to form zinc hydroxide and with oxygen to form zinc phosphate.…”

Energy-band alignment of II-VI/Zn3P2 heterojunctions from x-ray photoemission spectroscopy

“…[11][12][13][14][15] The solar energy-conversion efficiencies of these devices to date are less than $2%. Nevertheless, in some cases, the V OC and J SC values surpass those of Mg/Zn 3 P 2 Schottky barriers, suggesting that efficiency enhancements are possible through the use of a heterojunction solar cell design.…”

Thin Film Solar Cells Using Earth-Abundant Materials

“…Zinc phosphide homo-junctions have been difficult to make. However, even a zinc phosphide hetero-junction solar cell has not been successful with an efficiency range around 2% [11,85,86].…”