Introduction

The laser scanning technique has been used to bring out spatial inhomogeneities in semiconductor devices. for solar cells, in particular, the method is extensively used to study defects such as cracks, localized shunt, grain boundaries, foreign particle sites, poor metallization regions and non-ohmic back contact regions.this instrument enables fast scanning of solar cells (typical time is 2 - 3 seconds) for routine measurements, and slow scanning for permanent records on an X - Y recorder whenever required. The laser spot can be brought backward or moved forward to pin-point a defect on a solar cell by driving two galvanometer motors to deflect the beam from a He - Ne laser.

Special Features

The number of lines scanning the surface of a solar cell can be set at 16, 32, 64, 128 or 240. Line scan speed is variable from 2.4/min to 400/sec. Modes of scanning:single or multiple scan. Built-in, lock-in amplifier for weak signals with a chopper frequency of 294 Hz. During high speed operation, the X - Y recorder is automatically disconnected. It provides both Y and Z modulation signals for display on a CRO. Provision for independent line and frame reset. Facility to move the laser spot backward. Digital line counter on panel. Scans solar cells optically for defects.

Prospective Users

Solar product manufacturers

Keywords: Solar, cells, optical scanner

Type of Technology: Instrument

Contact:

Managing Director
Foundation for Innovation and Technology Transfer (FITT)
Indian Institute of Technology, Delhi
Hauz Khas, New Delhi-110016, INDIA
Tel : 91-011-26597167, 26857762, 26581013, 26597153
Fax : 91-011-26851169
E-mail : drkdpn@gmail.com