Graphitic carbon/n-CdTe Schottky-type heterojunction solar cells prepared by electron-beam evaporation

• The effect of interface states on current transport at forward bias was observed.
• The graphitic carbon/n-CdTe Schottky-type heterojunctions are linearly graded junctions.
• The photo-induced charge carriers mainly recombine within the neutral region.

We report on the analysis of the electrical and photoelectrical properties of graphitic carbon/n-CdTe Schottky-type heterojunction solar cells, which have been prepared by the deposition of transparent graphitic carbon films of nanometer thickness onto freshly cleaved n-CdTe substrates by the electron-beam evaporation technique. The presence of the electrically-active interface states at the heterojunction interface was revealed from the analysis of the dominating current transport at forward and reverse bias and from the capacitance–voltage characteristics. The unoptimized graphitic carbon/n-CdTe Schottky-type heterojunctions possess a rectification ratio of RR = 1390 and produce a maximum short circuit current density of Jsc = 8.47 mA cm−2, an open-circuit voltage of Voc = 0.435 V and fill factor of FF = 0.37 under standard illumination conditions (100 mW cm−2 AM 1.5).