High photoresponsivity of a p-channel InGaP/GaAs/InGaAs double heterojunction pseudomorphic modulation-doped field effect transistor

In this letter, we report the electrical and optical characteristics of $p$ -channel ${\mathrm{In}}_{\mathrm{0.13}}{\mathrm{Ga}}_{\mathrm{0.87}}\mathrm{As}$ double heterojunction pseudomorphic modulation-doped field effect transistor (MODFET) structure grown by gas source molecular beam epitaxy. The Hall mobility and the density of 2-DHGs (two-dimensional hole gases) in the pseudomorphic ${\mathrm{In}}_{\mathrm{0.13}}{\mathrm{Ga}}_{\mathrm{0.87}}\mathrm{As}$ channel were measured to be 250 ${\mathrm{cm}}^{\mathrm{2}}/\mathrm{V\hspace{0.17em}s}$ and ${\text{1.9×10}}^{12}\hspace{0.17em}{\mathrm{cm}}^{\mathrm{-2}}$ at 300 K, and 5800 ${\mathrm{cm}}^{\mathrm{2}}/\mathrm{V\hspace{0.17em}s}$ and ${\text{1.5×10}}^{12}\hspace{0.17em}{\mathrm{cm}}^{\mathrm{-2}}$ at 23 K, respectively. The fabricated $p$ -channel MODFET shows a good mobility property which is due to high valence band discontinuity of InGaP/GaAs/InGaAs double barriers. The peak energy in the photoluminescence spectrum from the $p$ -channel pseudomorphic MODFET structure was found to be 1.4 eV (λ=881 nm). The photoresponsivity with this modified pseudomorphic MODFET structure shows outstandingly better than that of a pin photodiode, particularly at low incident optical power.