Abstract
In this paper pulsed laser deposition (PLD) methods are used to study p-n CdTe/CdS heterojunctions fabricated in-situ. In-situ film deposition allows higher quality p-n interfaces by minimizing spurious contamination from the atmosphere. Morphologic and structural analyses were carried for CdTe films deposited on various substrates and different deposition conditions. The electrical characteristics and performance of the resulting p-n heterojunctions were studied as function of substrate and post-deposition anneal temperature. In-situ growth results on diodes with a rectification factor of ~105, an ideality factor <2, and a reverse saturation current ~10−8A. The carrier concentration in the CdTe film was in the range of ~1015cm−3, as measured by C-V methods. The possible impact of sulfur diffusion from the CdS into the CdTe film is also investigated using High Resolution Rutherford Back-Scattering.
•In situ pulse laser deposited CdTe/CdS heterojunctions with sharp interfaces.•220°C deposition and 400°C anneal yield diodes with very low reverse currents.•RBS results show sulfur diffusion from CdS into the CdTe films.•These diodes are ideal for photodetectors given the low reverse current.