Infrared photoresponse from pn-junction Mg2Si diodes fabricated by thermal diffusion Original Research Article

We fabricated pn-junction diodes by thermal diffusion of Ag acceptor into n-type melt-grown Mg2Si single-crystalline substrates (electron concentration=2×1015 cm−3) to investigate the infrared photoresponse of the material. The estimated hole concentration at the p-side of the diode diffused with Ag at 550 °C was 3×1018 cm−3. Current–voltage measurement of the diodes showed sound rectifying characteristics even at 300 K. A clear photoresponsivity with a photon energy threshold of approximately 0.6 eV was observed from the diode, showing promise for application in infrared light detection devices at wavelengths of 1.2–2 μm.