The dependence of a-Si:H/c-Si solar cell generator and spectral response characteristics on heterojunction band discontinuities

Eschrich, Heinz; Bruns, J.; Elstner, L.; Swiatkowski, C.

doi:10.1016/0022-3093(93)91098-n

Cited by 20 publications

(3 citation statements)

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“…Hence, the "observed V bi " calculated from the high-frequency 1/C 2 -V plot through the Mott-Schottky analysis is V hf bi = φ 0 c−Si = 0.86 V. Using (1c), (1d) or (5), ΔE V is found to be 0.49 eV. This value of ΔE V matches closely with several studies reported in the literature [19], [33]- [38]. In addition, we note that the V lf bi = 0.74 V estimated from low-frequency 1/C 2 -V plot through the Mott-Schottky analysis can provide the extent of c-Si band bending in the inversion layer as shown in Fig.…”

Section: δE V From C-v Measurementssupporting

confidence: 84%

Multiprobe Characterization of Inversion Charge for Self-Consistent Parameterization of HIT Cells

Chavali

Khatavkar

Kannan³

et al. 2015

IEEE J. Photovoltaics

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The performance of modern a-Si/c-Si heterojunction (HIT) solar cells is dictated by a complex interplay of multiple device parameters. A single characterization experiment [e.g., light current-voltage (I-V)] can be fitted with a set of parameters, but this set may not be unique and is, therefore, questionable as the basis for future design/optimization. In this paper, we use multiple (quasi-orthogonal) measurement techniques to uniquely identify the key parameters that dictate the performance of HIT cells. First, we study the frequency, voltage, and temperature response of inversion charge (Q Inv ) to create the theoretical basis for characterization of key device parameters, namely, the thickness of the i-layer at the front interface (t i a −S i ), a-Si/c-Si heterojunction valence band discontinuity (ΔE V ), built-in potentials in a-Si (φ a −S i ) and c-Si (φ c −S i ) regions, etc. Next, we simulate various characterization measurements, such as capacitance-voltage (C-V) and impedance spectroscopy, which probe Q Inv and explain the parameter extraction procedure from these measurements. Subsequently, we use the algorithm/procedure just developed to extract the aforementioned parameters for an industrial-grade HIT sample. Finally, we extend this quasi-orthogonal characterization framework by correlating the C-V characteristics with the ubiquitous light and dark I-V characteristics to demonstrate the consistency of the developed theory and uniqueness of the parameter extracted. The unique parameter set thus obtained can simultaneously provide a basis for the interpretation of the experimental measurements and can also be used for the design/optimization of these solar cells.

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Section: δE V From C-v Measurementssupporting

confidence: 84%

Multiprobe Characterization of Inversion Charge for Self-Consistent Parameterization of HIT Cells

Chavali

Khatavkar

Kannan³

et al. 2015

IEEE J. Photovoltaics

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“…9(b). [37][38][39][40][41] That is to say, the i/n + interface band offset will not lead to the signicant decrease of FF. 9(b), the FF does not show a sharp decrease until DE c is larger than 0.4 eV, the value is similar to that other groups have concluded.…”

Section: Resultsmentioning

confidence: 99%

Optimization of the window layer in large area silicon heterojunction solar cells

Zhang

Yang

et al. 2017

RSC Adv.

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Silicon heterojunction solar cells have shown great advantage due to their large open-circuit voltage which induces a high energy conversion efficiency. However, the short-circuit current density is limited by the high light absorption of an n-type amorphous silicon window layer in the short-wavelength range. Here an amorphous silicon oxide film was introduced to replace the window layer. The increasing oxygen content in amorphous silicon oxide layers leads to the enlarged optical band gap and the enhanced short-wavelength transmittance. As a result, the short-circuit current density increases obviously which comes from the high transmittance of amorphous silicon oxide films due to the wider band gap. Furthermore, the highly phosphorous-doped amorphous silicon layer was introduced to improve the contact between transparent conductive oxide layer and n-type amorphous silicon oxide layer. The carrier transport property is enhanced and thus the fill factor increases significantly. Finally, a silicon heterojunction solar cell with an area of 238.95 cm 2 was prepared, yielding a total-area efficiency up to 21.1%. Overall, the results indicate that amorphous silicon oxide films can be applied to silicon heterojunction solar cells as a window layer, which provides a new route to obtain higher energy conversion efficiency.rsc.li/rsc-advances 9258 | RSC Adv., 2017, 7, 9258-9263This journal is

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“…The a-Si:H/c-Si heterojunction has been investigated as a promising candidate in many semiconductor device microelectronic and photovoltaic applications. A lot of research work has been carried out for the last 30 years on amorphous/crystalline heterojunctions because of their application in photovoltaic field [1][2][3][4][5][6][7][8][9][10][11]. Although n-type wafers are usually used in commercial HIT solar cells, p-type c-Si wafer/substrates are attracting more attention by researchers due to lower material cost and popularity in the photovoltaic industry.…”

Section: Introductionmentioning

confidence: 99%

Effect of the front-metal work function on the performance of a-Si:H(n+)/a-Si:H(i)/c-Si(p) heterojunction solar cells

2019

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The present study investigates the effect of the front-metal work function on the energy band diagram and J-V characteristics under illumination of metal/a-Si:H(n +)/a-Si:H(i)/c-Si(p) heterojunction solar cells (HIT) by means of AFORS-Het device simulations supported by equivalent circuit modeling. It is found that for the heavily doped a-Si:H(n +) region, when the metal work function (m) is not small enough to ensure a good ohmic contact (3.9 ≤ m ≤ 4.47 eV), the observed decrease in the conversion efficiency (about 0.9%) with m are due to the increase in the series resistance R s. On the other hand, when m exceeds 4.47 eV, the degradation of the open-circuit voltage V oc (46 mV) and consequently the conversion efficiency (about 3.3%) is related to the rectifying Schottky barrier at the metal/a-Si:H(n +) interface. Moreover, for moderately doped a-Si:H(n +) regions and large front-metal work function, the carrier recombination in the bulk increases significantly. The active electron density is reduced, and consequently, a strong enhancement of the dark current is observed which leads to a serious V oc degradation. The J-V characteristics obtained from the circuit model analysis are in good agreement with the simulated results for different metal work functions.

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The dependence of a-Si:H/c-Si solar cell generator and spectral response characteristics on heterojunction band discontinuities

Cited by 20 publications

References 1 publication

Multiprobe Characterization of Inversion Charge for Self-Consistent Parameterization of HIT Cells

Multiprobe Characterization of Inversion Charge for Self-Consistent Parameterization of HIT Cells

Optimization of the window layer in large area silicon heterojunction solar cells

Effect of the front-metal work function on the performance of a-Si:H(n+)/a-Si:H(i)/c-Si(p) heterojunction solar cells

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