Probing carrier lifetimes in photovoltaic materials using subsurface two-photon microscopy

Barnard, Edward S.; Hoke, Eric T.; Connor, Stephen T.; Groves, J. R.; Kuykendall, Tevye; Yan, Z.; Samulon, E. C.; Bourret-Courchesne, Edith; Aloni, Shaul; Schuck, P. James; Peters, Craig H.; Hardin, Brian E.

doi:10.1038/srep02098

Cited by 69 publications

(45 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…32 Therefore, any improvement in the surface by LT should lead to an increase in measured lifetime by SP-TRPL as is indeed seen in the data in Fig. 7.…”

Section: Resultssupporting

confidence: 56%

Reduction of Fermi level pinning and recombination at polycrystalline CdTe surfaces by laser irradiation

Simonds

Kheraj

Palekis

et al. 2015

Journal of Applied Physics

View full text Add to dashboard Cite

Laser processing of polycrystalline CdTe is a promising approach that could potentially increase module manufacturing throughput while reducing capital expenditure costs. For these benefits to be realized, the basic effects of laser irradiation on CdTe must be ascertained. In this study, we utilize surface photovoltage spectroscopy (SPS) to investigate the changes to the electronic properties of the surface of polycrystalline CdTe solar cell stacks induced by continuous-wave laser annealing. The experimental data explained within a model consisting of two space charge regions, one at the CdTe/air interface and one at the CdTe/CdS junction, are used to interpret our SPS results. The frequency dependence and phase spectra of the SPS signal are also discussed. To support the SPS findings, low-temperature spectrally-resolved photoluminescence and time-resolved photoluminescence were also measured. The data show that a modest laser treatment of 250 W/cm 2 with a dwell time of 20 s is sufficient to reduce the effects of Fermi level pinning at the surface due to surface defects. V C 2015 AIP Publishing LLC. [http://dx.

show abstract

“…32 Therefore, any improvement in the surface by LT should lead to an increase in measured lifetime by SP-TRPL as is indeed seen in the data in Fig. 7.…”

Section: Resultssupporting

confidence: 56%

Reduction of Fermi level pinning and recombination at polycrystalline CdTe surfaces by laser irradiation

Simonds

Kheraj

Palekis

et al. 2015

Journal of Applied Physics

View full text Add to dashboard Cite

show abstract

“…Depth-resolved PL lifetime measurements [20,21] show that carrier lifetime is greatly increased a few microns below the surface because of reduced surface recombination. Similarly, the double heterostructure used here has previously been shown to increase PL lifetime due to carriers being separated from the surface [12].…”

Section: Discussionmentioning

confidence: 99%

Carrier Decay and Diffusion Dynamics in Single-Crystalline CdTe as Seen via Microphotoluminescence

et al. 2014

View full text Add to dashboard Cite

The ability to spatially resolve the degree to which extended defects impact carrier diffusion lengths and lifetimes is important for determining upper limits for defect densities in semiconductor devices. We show that a new spatially and temporally resolved photoluminescence (PL) imaging technique can be used to accurately extract carrier lifetime values in the immediate vicinity of dark-line defects in CdTe=MgCdTe double heterostructures. A series of PL images captured during the decay process show that extended defects with a density of 1.4 × 10 5 cm −2 deplete photogenerated charge carriers from the surrounding semiconductor material on a nanosecond time scale. The technique makes it possible to elucidate the interplay between nonradiative carrier recombination and carrier diffusion and reveals that they both combine to degrade the PL intensity over a fractional area that is much larger than the physical size of the defects. Carrier lifetimes are correctly determined from numerical simulations of the decay behavior by taking these two effects into account. Our study demonstrates that it is crucial to measure and account for the influence of local defects in the measurement of carrier lifetime and diffusion, which are key transport parameters for the design and modeling of advanced solar-cell and light-emitting devices.

show abstract

“…The procedure allows one to generate carriers at any desired depth inside the material, so that surface and bulk contributions can be disentangled in the TRPL response. We refer to the literature 4,5 for details on the operating principle and experimental setups.…”

Section: Introductionmentioning

confidence: 99%

Probing surface recombination velocities in semiconductors using two-photon microscopy

Gaury

Haney

2016

Journal of Applied Physics

View full text Add to dashboard Cite

The determination of minority-carrier lifetimes and surface recombination velocities is essential for the development of semiconductor technologies such as solar cells. The recent development of two-photon time-resolved microscopy allows for better measurements of bulk and subsurface interfaces properties. Here we analyze the diffusion problem related to this optical technique. Our three-dimensional treatment enables us to separate lifetime (recombination) from transport effects (diffusion) in the photoluminescence intensity. It also allows us to consider surface recombination occurring at a variety of geometries: a single plane (representing an isolated exposed or buried interface), two parallel planes (representing two inequivalent interfaces), and a spherical surface (representing the enclosing surface of a grain boundary). We provide fully analytical results and scalings directly amenable to data fitting, and apply those to experimental data collected on heteroepitaxial CdTe/ZnTe/Si.

show abstract

Probing carrier lifetimes in photovoltaic materials using subsurface two-photon microscopy

Cited by 69 publications

References 32 publications

Reduction of Fermi level pinning and recombination at polycrystalline CdTe surfaces by laser irradiation

Reduction of Fermi level pinning and recombination at polycrystalline CdTe surfaces by laser irradiation

Carrier Decay and Diffusion Dynamics in Single-Crystalline CdTe as Seen via Microphotoluminescence

Probing surface recombination velocities in semiconductors using two-photon microscopy

Contact Info

Product

Resources

About