Properties of electrodeposited germanium thin films

In this paper, the results of Ge film deposited by electroplating method was studied and showed the possibility of making a NIRS sensor by the Ge film. Cu/Ti double layer structure could use the cathode electrode on the glass substrate during the GeCl₄ electroplating. The deposition rate of electroplating Ge film was 100 nm/h, however, that rate was improved to 570 nm/h by introducing a spacer between Cu thin film and extraction electrode and Ar gas bubbling. The oxygen content of as-deposited film was about 10%, however, this value reduced to lower than 1% by using the Ar bubbling. The deposited film was amorphous and its optical band gap was 0.73 eV. 200 nm-thick Ge film was formed on flexible substrate by electroplating method.