InMnAs/InAs Heterojunctions for High-Field Magnetic Sensors

The devices are fabricated by epitaxially depositing InMnAs films (t 500 nm) on nInAs substrates via metal-organic vapor phase epitaxy (MOVPE). Mn is an acceptor in InAs, making the InMnAs films p-type. Mesa diodes (d = 250 pm) are patterned using conventional photolithography and wet etching; the device schematic is shown in Fig. 1. Rectifying behavior is observed. We have previously reported on the junction transport mechanisms and low-field (H < 0.5 T) magnetoresistance in InMnAs/InAs diodes [1]. It was found that a large magnetoresistance occurs when the forward-bias junction transport is dominated by high injection diffusion. In the present study, we have measured the magnetoresistance in magnetic fields up to 9 T, at temperatures ranging from 25 to 295 K.