Effect of epitaxial layer's thickness on spectral response of 4H‐SiC p‐i‐n ultraviolet photodiodes.

4H‐SiC ultraviolet p‐i‐n photodiodes with four different epitaxial structures were fabricated. The experimental results prove that both a thin P+‐type Ohmic contact layer and a thick intrinsic layer were indispensible for a high‐performance ultraviolet p‐i‐n photodiode. A 4H‐SiC p‐i‐n photodiode with responsivity as high as 0.139 A/W at 278 nm incident wavelength was achieved. Meanwhile, within a certain wavelength range, the peak response wavelength of an ultraviolet p‐i‐n photodiode would be modulated by properly varying the thicknesses of P+‐type layer and the intrinsic layer. Moreover, the theoretical calculation was carried out to further authorise the experimental results. [ABSTRACT FROM AUTHOR]