InGaAsN metal-semiconductor-metal photodetectors with Modulation-doped heterostructures

InGaAsN metal-semiconductor-metal (MSM) photodetectors (PDs) with modulation-doped heterostructures have been successfully fabricated. It was found from capacitance-voltage measurements that carriers were well confined. Using thermionic emission theory and measured dark currents, it was found that effective Schottky barrier heights were 0.61, 0.72, 0.50, and 0.23 eV for the MSM-PDs with Al_0.2Ga_0.8As cap layer doping N_d=5times10¹⁶, 9times10¹⁶, 2times10¹⁷, and 6times10¹⁷ cm^-3, respectively. Furthermore, it was found that measured responsivities were 0.02, 0.14, and 0.22 A/W and for the MSM-PDs with N_d=5times10¹⁶, 9times10¹⁶, and 2times10¹⁷ cm^-3, respectively