Very low surface recombination velocities on p- and n-type silicon wafers passivated with hydrogenated amorphous silicon films

Dauwe, S.; Schmidt, Jan; Hezel, Rudolf

doi:10.1109/pvsc.2002.1190834

Cited by 72 publications

(51 citation statements)

References 13 publications

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“…In order to reduce the influence of surface recombination, the wafer was chemically polished and passivated with a-Si by PECVD according to the process described by Dauwe et al. 19 However, the effective lifetime measured on the passivated wafer is still lower than that measured on the ingot through transient-PCD with the maximum lifetime about 6ms at an excess carrier density of 5×10 14 cm -3 . The higher the bulk lifetime is, the larger the observed difference.…”

Section: Correlation Of Lifetime To Td Concentration In As-grown Smentioning

confidence: 99%

Investigating thermal donors in n-type Cz silicon with carrier density imaging

Schøn

Øvrelid

et al. 2012

AIP Advances

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A new method to map the thermal donor concentration in silicon wafers using carrier density imaging is presented. A map of the thermal donor concentration is extracted with high resolution from free carrier density images of a silicon wafer before and after growth of thermal donors. For comparison, free carrier density mapping is also performed using the resistivity method together with linear interpolation. Both methods reveal the same distribution of thermal donors indicating that the carrier density imaging technique can be used to map thermal donor concentration. The interstitial oxygen concentration can also be extracted using the new method in combination with Wijaranakula's model. As part of this work, the lifetime at medium injection level is correlated to the concentration of thermal donors in the as-grown silicon wafer. The recombination rate is found to depend strongly on the thermal donor concentration except in the P-band region

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Section: Correlation Of Lifetime To Td Concentration In As-grown Smentioning

confidence: 99%

Investigating thermal donors in n-type Cz silicon with carrier density imaging

Schøn

Øvrelid

et al. 2012

AIP Advances

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“…We have also given in Table VII, the values of the corresponding recombination speeds at the a-Si:H /c-Si front and the c-Si/a-Si:H rear HJs, as calculated by ASDMP, under AM1.5 illumination and 0 V. We find that for a well-passivated front interface ͑N ss Յ ϳ 3 ϫ 10 11 cm −2 ͒ the recombination speed at this HJ is less than 10 cm/s ͑Table VII͒, in good agreement with measured interface recombination speeds. 36 In Fig. 7͑a͒, we plot the light J-V characteristics and in Fig.…”

Section: E Sensitivity Of the Solar Cell Output To The Defect Densitmentioning

confidence: 99%

Carrier transport and sensitivity issues in heterojunction with intrinsic thin layer solar cells on N-type crystalline silicon: A computer simulation study

Rahmouni¹,

Datta

Chatterjee

et al. 2010

Journal of Applied Physics

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Heterojunction with intrinsic thin layer or "HIT" solar cells are considered favorable for large-scale manufacturing of solar modules, as they combine the high efficiency of crystalline silicon ͑c-Si͒ solar cells, with the low cost of amorphous silicon technology. In this article, based on experimental data published by Sanyo, we simulate the performance of a series of HIT cells on N-type crystalline silicon substrates with hydrogenated amorphous silicon ͑a-Si:H͒ emitter layers, to gain insight into carrier transport and the general functioning of these devices. Both single and double HIT structures are modeled, beginning with the initial Sanyo cells having low open circuit voltages but high fill factors, right up to double HIT cells exhibiting record values for both parameters. The one-dimensional numerical modeling program "Amorphous Semiconductor Device Modeling Program" has been used for this purpose. We show that the simulations can correctly reproduce the electrical characteristics and temperature dependence for a set of devices with varying I-layer thickness. Under standard AM1.5 illumination, we show that the transport is dominated by the diffusion mechanism, similar to conventional P/N homojunction solar cells, and tunneling is not required to describe the performance of state-of-the art devices. Also modeling has been used to study the sensitivity of N-c-Si HIT solar cell performance to various parameters. We find that the solar cell output is particularly sensitive to the defect states on the surface of the c-Si wafer facing the emitter, to the indium tin oxide/P-a-Si:H front contact barrier height and to the band gap and activation energy of the P-a-Si:H emitter, while the I-a-Si:H layer is necessary to achieve both high V oc and fill factor, as it passivates the defects on the surface of the c-Si wafer. Finally, we describe in detail for most parameters how they affect current transport and cell properties.

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“…10"'L'2~""""'~~"""""~""""""""""''''''''''':':'''""'''''''''''-::-I 10 10'3 10 14 10'5 Injection level LIn (em-3 ) Figure 1: Effective lifetime as a function of the excess carrier density for low resistivity n-type (275 Ilm, <100>, 1_9 n cm) float zone c-Si substrate passivated with a 30, 15 and 7 nm thick AI203 film_ [7] In values for a B-doping concentra Ion > cm were extracted from the measured emitter saturation current density on B-doped p-type emitters as discussed in detail in a separate publication_ [8] The effective surface recombination values for lightly B-doped c-Si were calculated assuming an infinite bulk lifetime and using the best values published in the studies of Kerr et aL [6,9,10] and Dauwe et aL [9] Injection level (em-3 ) The excellent level of surface passivation by AI203 was also confirmed by solar cell device performance. AI203 applied at the rear of p-type c-Si solar cells yielded a maximum efficiency of 20.6 %.…”

Section: Introductionmentioning

confidence: 99%