Investigation on properties of electron-beam treated Mo back contact layer prepared by DC sputtering method

Molybdenum (Mo) has been used as back contact layer in chalcopyrite solar cells family (CulnSe2 and its alloys) because it showed the excellence of electrical properties such as low resistivity at the Mo interference. Generally, there are strong corrleations between working pressure and properites such as adhesion and conductivity during deposition of Mo layer. Electrical properites might be inversely proportional to adehsion between Mo layer and glass substrate. Several methods have been executed for improvement of electrical properties and ahesion. In this study, DC sputtered Mo back contact layers on sodalime glass were prepared with working pressure range of 1-10 mTorr, and then all samples were treated by rounded exposure of electron beam at DC power of 3 kV for 5 minutes. After electron-beam treatement, all samples showed the lower resisitivity and sheet resisitance than as-deposited Mo layers. As working pressure decreased, grain size of e-beam treated samples gradually increased up to 30.7 nm. E-beam treated Mo layer might be a good candidate as back contact layer of tandem structured CIS families thin film solar cells.