Dual-band MgZnO ultraviolet photodetector integrated with Si

We have constructed a dual-band ultraviolet photodetector by growing high quality MgxZn1-xO layers on Si substrate with molecular beam epitaxy. The device performance was studied by current-voltage, capacitance-voltage, spectra photoresponse, and time-resolved photoresponse characterizations. It demonstrates a high UV/visible light rejection ratio of more than 2 orders of magnitude and a fast response speed of less than 100 ms. The cutoff wavelength can be at solar-blind (280 nm)/visible-blind (301 nm) region by applying 1 V forward/2 V reverse bias. The working principle of the dual-band photodetector was finally investigated by interpretation of the specific carrier transport behavior with the energy band diagram. (C) 2013 AIP Publishing LLC [http://dx.doi.org/10.1063/1.4802486]