Modulated photoluminescence studies for lifetime determination in amorphous-silicon passivated crystalline-silicon wafers

Quasi-steady-state photoluminescence is a versatile technique to determine carrier lifetime in silicon. A recent approach extracts carrier lifetime without a priori information about dopant concentration [Appl. Phys. Lett. 97, 092109 (2010)]. It utilizes the phase shift between a time-modulated optical irradiation and the radiative recombination of a sample, while requiring a minimum of two measurements. The present paper is aimed at a generalization thereof that requires only one measurement. It brings about a substantial experimental simplification, significantly improved accuracy and precision, and it opens up paths to access material properties other than lifetime

Section: Peak Shift Approachmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Self‐sufficient minority carrier lifetime in silicon from quasi‐steady‐state photoluminescence

Giesecke

Schubert

Warta

2012

“…Thus, some other mechanism, as increased surface passivation, should act to the benefit of PL emission to explain such a modified behavior. We could gain some deeper understanding of the phenomena with the measurement of the temperature dependence of carrier lifetime in the range 200–500 K, for instance with modulated PL . We also reported in Fig.…”

Section: Resultsmentioning

confidence: 76%

Suppression of the thermal quenching of photoluminescence in irradiated silicon heterojunction solar cells

Plantevin

Defresne

Cabarrocas

2016

We report on the decrease in photoluminescence (PL) intensity with the increase of the sample temperature (thermal quenching) in crystalline silicon and its suppression after ion irradiation. The crystalline silicon surface was passivated with intrinsic and doped hydrogenated amorphous silicon (a-Si:H) layer stacks as for making silicon heterojunction solar cell precursors. Low energy argon ion irradiation, in the range between 5 and 17 keV, was used for controlled defect formation either in the thin a-Si:H top layer or at the interface with the crystalline silicon beneath. The irradiation defects introduce radiative recombination centers in the a-Si:H as can be measured from PL at low temperature. Moreover, the irradiation and annealing result in a strong modification of the thermal quenching of the PL intensity up to 500 K, showing evidence for the strong reduction of thermally activated nonradiative recombinations at the amorphous-crystalline interface. This result can have implications in the field of crystalline silicon surface passivation.

“…[11] However, the interface states density could never be measured, and the quality of the device is generally assessed through the open circuit voltage of the cell or the effective lifetime in the c-Si wafer, measured from various techniques like photoluminescence, photoconductivity decay or from other techniques. [12] We here give a summary of our knowledge of the a-Si:H/c-Si interface in terms of device physics. We emphasize the role of strong inversion of the silicon surface in both (p) a-Si:H/(n) c-Si and (n) a-Si:H/(p) c-Si heterojunctions.…”

Section: Introductionmentioning

confidence: 99%

Recent Progress in Understanding the Properties of the Amorphous Silicon/Crystalline Silicon Interface

Kleider

Alvarez

Brüggemann

et al. 2019

The authors review experimental and modeling approaches developed at GeePs to have a better knowledge and understanding of the interface between hydrogenated amorphous silicon (a‐Si:H) and crystalline silicon (c‐Si) in heterojunction solar cells. The authors emphasize the existence of a strong inversion layer at the c‐Si surface for both (n) a‐Si:H/(p) c‐Si and (p) a‐Si:H/(n) c‐Si heterojunctions. Conductive probe atomic force microscopy reveals the existence of a conductive channel at the c‐Si surface. The analysis of complementary lateral planar conductance and capacitance measurements allows for a better description of the band diagram in both types of heterojunctions especially through the determination of band offset values. Furthermore, the passivation properties of the (i) a‐Si:H buffer layer are studied by modeling the volume defects in a‐Si:H with the defect‐pool model. In particular, the DOS in the very thin (i) a‐Si:H layers is much larger than in bulk (i) a‐Si:H because the Fermi level position favors defect creation. Surface defects in c‐Si at the a‐Si:H/c‐Si interface are then quantified and the general trends of effective lifetime measurements with the (i) a‐Si:H layer thickness can be explained, notably the increase of the effective lifetime in c‐Si with increasing the (i) a‐Si:H buffer thickness.