Energy-selective multichannel ultraviolet photodiodes based on (Mg,Zn)O

We report on the fabrication of photodiodes, employing rectifying contacts based on ternary (Mg,Zn)O thin films in wurtzite modification. We utilize a concept for forming a compositionally graded active layer, allowing the design of energy-selective, monolithic, and multichannel ultraviolet metal-semiconductor-metal photodetectors. In our device design, the filter layer blocking high energy irradiation is separated from the active layer and allows the tuning of cutoff energies and bandwidth of the photodiode. Here, the onset of absorption was tuned over 230 meV, and the bandwidth of the photodiodes was varied by 140 meV within the continuous composition spread of the active layer. (C) 2013 AIP Publishing LLC.