Visible-blind GaN Schottky barrier detectors grown on Si(111)

Abstract

We report novel GaN detectors grown by molecular beam epitaxy on Si(111) substrates. Wurtzite structure epitaxial GaN exhibits room-temperature photoluminescence with a band-edge-related emission width as narrow as 7 nm and intensities comparable to high quality layers grown on sapphire by metalorganic chemical vapor deposition. Spectral response of lateral geometry Schottky detectors shows a sharp cutoff at 365 nm with peak responsivities of $\text{∼0.05\hspace{0.17em}}\mathrm{A/W}$ at 0 V, and $\text{∼0.1\hspace{0.17em}}\mathrm{A/W}$ with a $\text{−4\hspace{0.17em}}\mathrm{V}$ bias. The dark current is $\text{∼60\hspace{0.17em}}\mathrm{nA}$ at $\text{−2\hspace{0.17em}}\mathrm{V}$ bias. The noise equivalent power is estimated to be ${\text{3.7×10}}^{\text{−9}}\hspace{0.17em}\mathrm{W}$ over the response bandwidth of 2.2 MHz.