Quantifying boron and phosphorous dopant concentrations in silicon from photoluminescence spectroscopy at 79 K

Liu, AnYao; Nguyen, Hieu T.; Macdonald, Daniel

doi:10.1002/pssa.201600335

Cited by 10 publications

(7 citation statements)

References 19 publications

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“…Luminescence spectroscopy has been demonstrated to be a powerful technique to investigate optoelectronic properties of various structures in crystalline silicon (c-Si) solar cells. Band-to-band photoluminescence (PL) spectra from c-Si have been used to extract fundamental parameters of the material such as the band-to-band absorption coefficient, − the radiative recombination coefficient, ,, temperature and doping dependencies , of the c-Si bandgap, dopant concentrations, , diffusion lengths of minority carriers in c-Si wafers , and bricks, as well as the light trapping capability of various plasmonic structures . Moreover, sub-bandgap PL spectra have been employed to investigate the nature of various defects in c-Si wafers, such as dislocations, − metal precipitates, oxygen precipitates, − or laser-induced defects. , In addition, some deposited thin films acting as both surface passivation and antireflection coating layers have also been demonstrated to emit strong PL signals at low temperatures.…”

Section: Introductionmentioning

confidence: 99%

Sub-Bandgap Luminescence from Doped Polycrystalline and Amorphous Silicon Films and Its Application to Understanding Passivating-Contact Solar Cells

Nguyen

Liu

Yan

et al. 2018

ACS Appl. Energy Mater.

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We report luminescence phenomena from doped polycrystalline silicon (poly-Si) films and their applications to study carrier transport properties in passivating-contact solar cells. Low-temperature luminescence spectra emitted from doped poly-Si layers are found to be very broad and stretched from the crystalline silicon (c-Si) luminescence peak to significantly lower energies. This suggests that these layers contain radiative defect levels whose energies are continuously distributed from the band edges to deep levels in the poly-Si bandgap. Moreover, photoinduced carriers inside poly-Si layers are found to be completely blocked by an ultrathin SiO x interlayer (∼1.3 nm). This demonstrates that there is no free-carrier coupling from poly-Si layers in practical passivating-contact solar cells. Finally, we demonstrate that the same principle can be applied to study carrier transport properties in hydrogenated amorphous silicon films.

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Section: Introductionmentioning

confidence: 99%

Sub-Bandgap Luminescence from Doped Polycrystalline and Amorphous Silicon Films and Its Application to Understanding Passivating-Contact Solar Cells

Nguyen

Liu

Yan

et al. 2018

ACS Appl. Energy Mater.

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“…A notable feature is that at low temperatures their spectra are much broader than those of c‐Si. In Figure , the full width at half maximum (FWHM) of the spectra is ≈150 meV, whereas that of c‐Si is ≈25 meV at 80 K . This broadening stems from the fact that the PL spectra from a‐Si:H and SiN are reported to be emitted by the carriers trapped at band‐tail states at the band edges, resulting in a relatively broad range of energies, rather than being emitted from the two sharp band edges, as is the case for c‐Si.…”

Section: Resultsmentioning

confidence: 99%

“…Thus, the shape and intensity of the emitted spectrum have direct relationships with the electrical and optical properties and thickness of the material. Many authors have utilized these relationships to extract fundamental properties of c‐Si such as the bandgap, absorption coefficient and radiative recombination coefficient, diffusion lengths of minority carriers, or doping density …”

Section: Introductionmentioning

confidence: 99%

Imaging the Thickness of Passivation Layers for Crystalline Silicon with Micron‐Scale Spatial Resolution Using Spectral Photoluminescence

et al. 2017

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Thin films deposited on crystalline silicon surfaces are critical components of many silicon-based devices, including high-efficiency photovoltaic cells. Knowledge of their optical and electronic properties is important in designing and fabricating efficient solar cells, especially as the device complexity increases and includes micron-scale features. Here, a camera-based photoluminescence (PL) technique is developed to image the thickness of specific passivating films on silicon wafers. The technique is entirely contactless and nondestructive, requires minimal sample preparation, and provides a large dynamic range in terms of field of view, with micron-scale spatial resolution possible. It retains the advantages of PL imaging, a mainstream technique for photovoltaic material and device characterization, and it has some extra capabilities similar to those of ellipsometry. This newly developed technique is demonstrated on hydrogenated amorphous silicon and silicon nitride films, two important passivation technologies for high-efficiency silicon solar cells.

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“…In this work, the spectra measured on samples with different doping concentrations were modelled based on a PL curve that was measured on a lightly doped silicon wafer ( N A < 1 × 10 15 cm −3 ) which has minimum influence from the dopants at liquid nitrogen temperature . Note that no model was applied to the mentioned PL spectra although in principle it can be modelled with the Maxwell‐Boltzmann distribution .…”

Section: Resultsmentioning

confidence: 99%

Reconstructing photoluminescence spectra at liquid nitrogen temperature from heavily boron‐doped regions of crystalline silicon solar cells

Nguyen

Liu

et al. 2017

Progress in Photovoltaics

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When measured at low temperature (79 K), the photoluminescence (PL) spectra from silicon wafers containing a diffused heavily doped layer exhibit a second peak due to band gap narrowing in the diffused region. This work aims to decompose this peak into components arising from the various doping concentrations within the diffused layer. Whilst the peak position of silicon band-to-band PL spectra changes significantly with the doping concentration in silicon, the shape of the spectra also varies strongly with doping concentrations due to the broadening effects of band-filling and band-tail states. By measuring PL spectra on a range of uniformly heavily doped wafers, we show that these changes in spectral position and shape can be accurately modelled for doping concentrations above 1 × 10 19 cm −3 using simple parameterisations, with minimal impact of variations in excitation intensity or injection level. This allows the PL spectra for a range of arbitrary doping concentrations to be reconstructed. We then show that the PL spectra from a thermally boron-diffused wafer, in which the boron concentration changes with depth, can be reconstructed based on a superposition of PL spectra arising from the layers of different doping beneath the surface. Furthermore, the scaling factor for each layer can be accurately estimated based on the doping profile and the fraction of incident light absorbed in the layer.

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Quantifying boron and phosphorous dopant concentrations in silicon from photoluminescence spectroscopy at 79 K

Cited by 10 publications

References 19 publications

Sub-Bandgap Luminescence from Doped Polycrystalline and Amorphous Silicon Films and Its Application to Understanding Passivating-Contact Solar Cells

Sub-Bandgap Luminescence from Doped Polycrystalline and Amorphous Silicon Films and Its Application to Understanding Passivating-Contact Solar Cells

Imaging the Thickness of Passivation Layers for Crystalline Silicon with Micron‐Scale Spatial Resolution Using Spectral Photoluminescence

Reconstructing photoluminescence spectra at liquid nitrogen temperature from heavily boron‐doped regions of crystalline silicon solar cells

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