Scanning room temperature photoluminescence in SiN_x:H layers

¹ University of South Florida, 4202 E Fowler Avenue, Tampa, Florida, 33620, USA
² Georgia Institute of Technology, 777 Atlanta Dr., Atlanta, GA 30332, USA
³ Evergreen Solar, 259 Cedar Hill St., Marlboro, MA 01752, USA

Corresponding author: ostapenk@eng.usf.edu

Received: 1 July 2003
Accepted: 18 December 2003
Published online: 15 July 2004

Abstract

We report on spectroscopic photoluminescence (PL) mapping of solar-cell-grade mc-Si ribbon wafers. We observe under UV excitation a broad visible emission from the SiN_x:H layer. The samples covered with SiN_x:H were subjected to rapid thermal processing at different temperatures, and PL maps were measured before and after treatment. We observed that after RTP treatment the intensity of the PL band was significantly increased, which indicates further reduction of non-radiative defects. The magnitude of these increases depends on the RTP conditions. The visible PL band exhibits a reversible photo quenching of the intensity under 325 nm HeCd laser excitation. The PL intensity can be recovered by annealing with the rate exhibiting a thermally activated behavior. The observed PL photo quenching reveals a metastable process in the SiN_x:H film under UV excitation. We demonstrate the possibility of creating a reversible luminescence micro-pattern on the SiN_x:H layer using a focused UV laser beam.