skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Effects of Absorber Near-Interface Compensation on Cd(Se,Te) Solar Cell Performance

Journal Article · · Solar Energy Materials and Solar Cells

Arsenic (As) has been shown to be an effective p-type dopant for CdTe, although high performance in As-doped devices remains difficult to achieve. Arsenic is prone to self-compensation in CdTe, as evidenced by the accumulation of dopant atoms in CdTe/Cd(Se,Te) near the interface with MgxZn1-xO (MZO). In this study, we use SCAPS 1D modeling software to investigate the effect of near-interface compensation, helping elucidate loss pathways in present-day As-doped devices and informing future growth directions. We consider three possible results of As accumulation: shallow donors, deep recombination centers, and a thin layer of excess acceptor accumulation. The reduction in near-interface carrier concentration caused by shallow donors is shown to improve open-circuit voltages (VOC), whereas deep levels are detrimental to all performance parameters. The thin charge layer affects capacitance-voltage (CV) measurements by reducing the depletion width while maintaining the same carrier concentration, replicating CV behavior that has been observed in actual devices. These results illustrate the importance of monitoring dopant accumulation within 100 nm of the interface, and suggest that reducing or eliminating the As concentration in this region would be beneficial. An undoped Cd(Se,Te) layer at the interface is suggested as a possible device structure to boost performance.

Research Organization:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Organization:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Solar Energy Technologies Office
DOE Contract Number:
Report Number(s):
NREL/JA-5K00-82980; MainId:83753; UUID:49e79d2a-33e4-4487-8751-ae9ddbe452dd; MainAdminID:65232
Journal Information:
Solar Energy Materials and Solar Cells, Vol. 246
Country of Publication:
United States

References (23)

Analysis and optimisation of the glass/TCO/MZO stack for thin film CdTe solar cells journal December 2018
Polycrystalline CdTe photovoltaics with efficiency over 18% through improved absorber passivation and current collection journal March 2018
Polycrystalline CdSeTe/CdTe Absorber Cells With 28 mA/cm 2 Short-Circuit Current journal January 2018
Roles of bandgrading, lifetime, band alignment, and carrier concentration in high-efficiency CdSeTe solar cells journal August 2020
Exceeding 20% efficiency with in situ group V doping in polycrystalline CdTe solar cells journal August 2019
Understanding what limits the voltage of polycrystalline CdSeTe solar cells journal March 2022
Understanding arsenic incorporation in CdTe with atom probe tomography journal August 2018
Study of thin film poly-crystalline CdTe solar cells presenting high acceptor concentrations achieved by in-situ arsenic doping journal June 2019
Tabulated values of the Shockley–Queisser limit for single junction solar cells journal June 2016
The roles of carrier concentration and interface, bulk, and grain-boundary recombination for 25% efficient CdTe solar cells journal June 2017
Experimental and theoretical comparison of Sb, As, and P diffusion mechanisms and doping in CdTe journal January 2018
High p-type doping, mobility, and photocarrier lifetime in arsenic-doped CdTe single crystals journal May 2018
Comparative study of As and Cu doping stability in CdSeTe absorbers journal June 2021
Overcoming Carrier Concentration Limits in Polycrystalline CdTe Thin Films with In Situ Doping journal September 2018
Low-temperature and effective ex situ group V doping for efficient polycrystalline CdSeTe solar cells journal June 2021
Carrier density and lifetime for different dopants in single-crystal and polycrystalline CdTe journal November 2016
Self-compensation in arsenic doping of CdTe journal July 2017
Impact of dopant-induced optoelectronic tails on open-circuit voltage in arsenic-doped Cd(Se)Te solar cells journal September 2020
Dual-Wavelength Time-Resolved Photoluminescence Study of CdSe x Te 1-x Surface Passivation via Mg y Zn 1-y O and Al 2 O 3 journal January 2022
Modelling polycrystalline semiconductor solar cells journal February 2000
Impact of Carrier Concentration and Carrier Lifetime on MgZnO/CdSeTe/CdTe Solar Cells journal November 2020
Emitter/absorber interface of CdTe solar cells journal June 2016
The Influence of Conduction Band Offset on CdTe Solar Cells journal November 2017