Morphological and Compositional Analysis of Electrodeposited Indium (III) Sulfide (In2S3) Films

Maqsood Ali Mughal, Michael Jason Newell, Joshua Vangilder, Shyam Thapa, and Kayla Wood-Student Research Assistants; Robert Engelken, Bruce Johnson, and Ross Carroll-Faculty Mentors

Arkansas State University, Jonesboro, AR, USA

Reported Papers on Electrodeposition of Semiconductor Thin Films with Crack MorphologySemiconductor

MaterialElectrolyte Potential Cause for Cracks Reference

CdS Organic Thickness Fulp & Taylor, 1985

CdSDEG-water

mixturesIncorporation of solutes with

solvent/addition agentFulp & Taylor, 1985

Si Ionic Liquid Thickness, substrates, deposition voltage Oskam et. al., 2001

Bi2S3 Aqueous Solvents Begum A. et. al., 2011

CIGS Aqueous % composition of precursor Chemicals Visvanathan S. et. al., 2011

CdS Organic Solvent and Piezoelectric Effect Abbas S, 2007

Cu-Ga-Se AqueousIncorporation of solutes with solvent/addition agent and %

composition of precursor solutionsOda Yuske D. et. al., 2006

Cu Aqueous Surface contamination Jack D. et. al., 2010

CdSe Aqueous Substrates Chowdhry R. I, 2011

Energy Dispersive X-Ray (EDS) Data - (Compositional Analysis)

Element Intensity Weight% Weight% Atomic%

C K 0.2918 0.00 0.00 0.00

O K 0.3395 5.51 0.72 17.43

Na K 0.7603 0.75 0.18 1.65Si K 0.9325 0.00 0.00 0.00S K 1.0708 34.79 0.47 54.93

Mo L 0.8870 0.00 0.00 0.00In L 0.9030 58.95 0.60 25.99

S/In Ratio 2.11

Fracture and Buckling Image Analysis Program

Morphological Analysis

Three-electrode Electrochemical Cell

Side View

Aerial View

The authors acknowledge the gracious support provided by Arkansas State University, National Science Foundation grant EPS-1003970 administered by the Arkansas Science and Technology Authority, and NASA grant NNX09AW22A administered by the Arkansas Space Grant Consortium. Dr. Alan Mantooth, Kathy Kirk, Dr. Greg Salamo, Dr. Omar Manasreh, Dr. Alex Biris, Dr. Tansel Karabacak, Dr. Hyewon Seo, and other collaborators at the University of Arkansas (Fayetteville, Little Rock, and Pine Bluff campuses) are also thanked, as are Dr. Keith Hudson and Laura Holland at ASGC, and Dr. Gail McClure, Cathy Ma, and Marta Collier at ASTA. The authors are also grateful for the ongoing support provided by Arkansas State University, particularly Dr. David Beasley, Dr. Rick Clifft, Dr. Paul Mixon, Dr. William Burns, Dr. Tom Risch, Dr. Tanja McKay and Dr. Andrew Sustich.

Post-annealed electrodeposition

Post-annealed electrodeposition (repeated

trials)

Horizontally positioned substrate-Mo

Electrodeposited at -0.685 V for 6 min. and at -0.7 V for 40

min. (repeated trials)

Pulse-plating (-0.8 V with 10 sec. delay) at120 oC for 50

min. Mo

Pulse-plating (-0.685 V with 10 sec. delay) at 70 oC for 95

min. FTO

Pulse-plating (-0.7 V with 15 sec. delay) at 150 oC for 48

min. FTO

Pulse-plating (-0.7 V with 10 sec. delay) at 80 oC for 75

min. ITO

Indium sulfide rings formation from sodium

thiosulfate as sulfur source-ITO

Electrodeposited at -0.685 V for 4 min with ethylene

glycol solvent

Current density: 0.75 mA/cm2

Electrodeposited at -0.7 V for 15 min. (sodium thiosulfate as

sulfur source)

Electrodeposited at -0.7 V for 50 min. at 160 oC

JWH: Electrodeposited at -0.8 V for 30 min in formamide solvent

Current density: 1.25 mA/cm2

Current density: 1.5 mA/cm2

Current density: 1 mA/cm2

Low resistance substrate-ITO at150 oC

Many different photovoltaic materials are deposited with various deposition techniques on a variety of substrates. In the last few years, notable progress have been made in understanding the growth mechanism of thin films for photovoltaic (PV) applications. Electrodeposition is a complex deposition technique that can lead to low-quality material regions (crack) in the semiconductor material. Such cracks form porous zones on the substrate and diminish the heterojunction interface quality of a PV cell.

Electrodeposited In2S3 (an indirect n-type semiconductor material-buffer layer) films were systematically and quantitatively investigated by varying the electrodeposition parameters including composition of the solution, current density, deposition time, and deposition temperature.

Introduction

§ Focus upon potential new PV materials and/or methods to reliably and inexpensively produce them as thin films.

§ Understand the growth mechanism of the deposited semiconductor material from electrodeposition.

§ Study the relationship between the electrodeposition parameters and their effect on the performance parameters.

§ Combining n-In2S3/p-CuInS2(or p-CdTe) to form a heterojunction junction solar cell.

§ Understand the operation and stability of the solar cell.

Research Objective

Exp. No.

L18 Design of Experiment DOE

Bath Composition

Current Density

(mA/cm2)Substrate

Deposition Time (min)

Deposition Temperature

(oC)

Mean Crack Density (/µm)

Mean Distance

b/w cracks (µm)

1 S 0.75 Mo 5 140 0 0

2 S 0.75 ITO 10 150 0.2739 3.7086

3 S 0.75 FTO 15 160 No Film

4 S 1.25 Mo 5 150 0.26352 3.9316

5 S 1.25 ITO 10 160 0.2658 4.1126

6 S 1.25 FTO 15 140 0.2153 4.6465

7 S 1.75 Mo 10 140 0.1234 9.7658

8 S 1.75 ITO 15 150 0.2763 3.6245

9 S 1.75 FTO 5 160 0.1731 5.7815

10 Na2S2O3.5H2O 0.75 Mo 15 160 0 0

11 Na2S2O3.5H2O 0.75 ITO 5 140 No Film

12 Na2S2O3.5H2O 0.75 FTO 10 150 0 0

13 Na2S2O3.5H2O 1.25 Mo 10 160 0.3630 2.7564

14 Na2S2O3.5H2O 1.25 ITO 15 140 No Film

15 Na2S2O3.5H2O 1.25 FTO 5 150 0.3154 3.1720

16 Na2S2O3.5H2O 1.75 Mo 15 150 0.2099 4.9213

17 Na2S2O3.5H2O 1.75 ITO 5 160 No Film

18 Na2S2O3.5H2O 1.75 FTO 10 140 0.17480165 5.7431238

Acknowledgements

Taguchi MethodTaguchi Methods are statistical methods developed by Genichi Taguchi to

improve the quality of manufactured goods, and more recently have also been applied to engineering, biotechnology, etc.Two basic goals of Taguchi Methods:

§ Quality Control§ Design of Experiments (DOE).

§ To determine the “best” combination of factors and levels to produce a “quality product”.

§ To measure the impact/sensitivity of deposition parameter levels on the characterized performance of a product using statistical analysis tools (Orthogonal Regression, ANOVA, etc.).

Main Effects Plot for Means (Mean Crack Density (/µm)