Surface Passivation of CdTe Single Crystals

Author

Reese, Matthew O. ; Burst, James M. ; Perkins, Craig L. ; Kanevce, Ana ; Johnston, Steven W. ; Kuciauskas, Darius ; Barnes, Teresa M. ; Metzger, Wyatt K.

Author_Institution

Nat. Renewable Energy Lab., Golden, CO, USA

Volume

5

Issue

1

fYear

2015

fDate

Jan. 2015

Firstpage

382

Lastpage

385

Abstract

Low open-circuit voltages (850-870 mV), due to excessive bulk and surface recombination, currently limit CdTe photovoltaic efficiencies. Here, we study surface recombination in single crystals with single-photon excitation time-resolved photoluminescence (1PE-TRPL) to measure minority carrier lifetimes. Typically, minority carrier lifetimes of untreated undoped CdTe material as measured by 1PE-TRPL are ~100 ps or less, even though their bulk lifetimes as measured by two-photon excitation TRPL can reach 100 ns. Such short 1PE-TRPL lifetimes indicate very high surface recombination velocities exceeding 100 000 cm/s. Here, we examine treatments that can reduce surface recombination and discuss different ways of evaluating their efficacy.

Keywords

II-VI semiconductors; cadmium compounds; carrier lifetime; minority carriers; passivation; photoluminescence; surface recombination; time resolved spectra; two-photon spectra; CdTe; minority carrier lifetimes; open-circuit voltages; photovoltaic efficiency; single-photon excitation time-resolved photoluminescence; surface passivation; surface recombination; two-photon excitation; voltage 850 mV to 870 mV; Charge carrier lifetime; Crystals; Passivation; Photoluminescence; Photovoltaic systems; Radiative recombination; Cadmium compounds; charge carrier lifetime; photoluminescence; photovoltaic cells;

fLanguage

English

Journal_Title

Photovoltaics, IEEE Journal of

Publisher

ieee

ISSN

2156-3381

Type

jour

DOI

10.1109/JPHOTOV.2014.2362298

Filename

6945796