Properties of CdTe layers deposited by a novel method -Pulsed Plasma Deposition

TL;DR

This paper introduces Pulsed Plasma Deposition (PPD), a novel low-temperature method for depositing high-quality, crystalline CdTe layers with low surface roughness, potentially reducing costs and material usage for thin film photovoltaics.

Contribution

The study presents PPD as a new low-temperature deposition technique for CdTe, achieving high crystallinity and low surface roughness, which could lower fabrication costs and improve material efficiency.

Findings

CdTe layers have a band gap of 1.50 eV, matching literature values.

Films are highly crystalline with a cubic phase and random grain orientation.

Surface roughness is extremely low at 4.6 nm RMS.

Abstract

CdTe and CdS are emerging as the most promising materials for thin film photovoltaics in the quest of the achievement of grid parity. The major challenge for the advancement of grid parity is the achievement of high quality at the same time as low fabrication cost. The present paper reports the results of the new deposition technique, Pulsed Plasma Deposition (PPD), for the growth of the CdTe layers on CdS/ZnO/quartz and quartz substrates. The PPD method allows to deposit at low temperature. The optical band gap of deposited layers is 1.50 eV, in perfect accord with the value reported in the literature for the crystalline cubic phase of the CdTe. The films are highly crystalline with a predominant cubic phase, a random orientation of the grains of the film and have an extremely low surface roughness of 4.6\pm0.7 nm r.m.s.. The low roughness, compared to traditional thermal deposition methods (close space sublimation and vapour transport) permits the reduction of the active absorber and n-type semiconductor layers resulting in a dramatic reduction of material usage and the relative deposition issues like safety, deposition rate and ultimately cost