Transition related to the Mn–Zn interaction was observed in photoluminescence (PL) study of the InMnP:Zn epilayer and the peak position blueshifted with increasing Mn concentration. X-ray photoelectron spectroscopy was used to clarify the blueshift of the PL peak. The binding energy shifts of Mn 2p and Zn 2p core levels indicative of the interaction between Mn and Zn were observed. This mutual interaction between Mn 2p and Zn 2p agrees with the result that the Mn-related transition in InMnP:Zn codoped with Zn is shifted to the higher energy region in comparison with InMnP without additional doping of Zn.

InMnP:Zn samples implanted with Mn (10at.%) were annealed at 350°C for 60s and at 450°C for 30s. Using transmittance electron microscopy, both single crystalline and polycrystalline structures containing MnP and InMn3 sized ∼20nm were observed depending on the annealing condition. These samples exhibited two different Curie temperatures: TC1 at 291K and another well above 291K. The high temperature-ferromagnetic behavior up to TC1 and above TC2 is believed to have originated from two magnetic MnP and InMn3 phases, respectively.

We investigated the device performances for a post-growth thermally treated In0.5Ga0.5As/GaAs quantum-dot infrared detector (QDIP). Device characteristics, such as dark current, photoluminescence (PL), and photocurrent spectra, have been studied and compared for the as-grown and thermally treated QDIPs. After the thermal treatment with a SiO2 capping layer, the dark current was increased, the PL peak position was blue-shifted, and the detection wavelength was redshifted due to In/Ga interdiffusion in the quantum dot (QD) structure. Furthermore, the activation energies estimated from the integrated PL intensities agreed well with the peak positions of the photocurrent spectra.

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