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

Abstract

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

Understanding and resolving the discrepancy between differential and actual minority carrier lifetime

“…(6) at a finite generation rate. A harmonically time-modulated phase-sensitive lifetime approach 7,8,[13][14][15][16][17] yields phase shifts corresponding to differential rather than actual lifetimes, irrespective of the existence of an additional steady-state bias light. In fact, a continuously time-modulated irradiation is the only true representative of the differential limit n !…”

“…We have proposed a related approach to determine injection-dependent lifetime from measured phase shifts (based on time-modulated photoluminescence) in the past. 7,8,13 Originally, this so-called self-sufficient approach 7 determined carrier lifetime from measured phase shifts via numeric solution of the continuity equation. With the theory of light-biased decay time derived herein, the above numeric procedure can be replaced by a very fast analytic calculation on the basis of Eq.…”

“…Also, numeric modeling of the phase shift between a time-modulated irradiation and excess carrier density revealed systematic deviations from actual lifetime for injection-dependent lifetimes. 7,8 The phase shift was greater than effective carrier lifetime in the case of a positive derivative of lifetime with respect to excess carrier density ds=dDn > 0, whereas it was less than lifetime in the case of a negative derivative ds=dDn < 0. Strikingly, this is a qualitative analogy to the findings of Brendel, Aberle, and Schmidt.…”

“…Following the self-consistent dynamic approach by Trupke et al, 6 we aimed at overcoming its requirement of assumptions about net dopant concentration under intermediate-to high-level injection conditions. 7 For this purpose, we initially interpreted the phase shift between time-modulated irradiation and photoluminescence intensity as the actual effective lifetime-as one might conclude from a quasisteady-state treatment of the time-dependent continuity equation. 8 However, measured phase shifts proved to only be equal to actual effective carrier lifetime in the special case of a vanishing injection dependence.…”

On the observation of electron-hole liquid luminescence under low excitation in Al2O3-passivated c-Si wafers

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1 Introduction Room-temperature photoluminescence (PL) spectroscopy has been widely used to characterize passivated c-Si wafers [1]. In particular, timeresolved PL measurements [2] or studies that combine PL with photocurrent measurements [3,4] have been successfully used to obtain quantitative results regarding carrier lifetime, i.e., passivation efficiency. In contrast, lowtemperature PL measurements have been scarcely explored for studies of passivation performance.

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