Photoluminescence Measurements in Interband Transition in Fast Neutron Irradiated In 0.07 Ga 0.93 As/A 10.4 Ga 0.6 As Mu
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ABSTRACT: Interband transitions in n-type InGaAs/AlGaAs multiple quantum wells were studied using a photoluminescence (PL) technique after the samples were irradiated with fast neutrons. It was observed that the PL intensity of the interband transition is reduced as the irradiation dose is increased. In Addition, the peak position energy of the interband transition was increased and then decreased as a function of irradiation dose. The results are explained in terms of electrons trapping, many-body effects, and irradiation-induced damages at the interfaces as well as in the well and barrier regions.
INTRODUCTION: Irradiation-induced defects in bulk Ill-V semiconductors have been the subject of many research interests in the last three decades or so [see for example Refs. 1, 2]. However, the irradiation effect on interfaces in superlattices and heterojunctions and on various transitions, such as intersubband and interband transitions, in multiple quantum wells have received little attention thus far. Gamma-ray irradiation effect on the intersubband transitions in InGaAs/AlGaAs multiple quantum wells have been recently reported [3]. A recent report [4] on the proton irradiation effect on GaAs quantum well lasers indicates that there is a wavelength shift in the lasing spectra. The interest in irradiation effects on multiple quantum wells and superlattices spurs from the fact that many devices based on III-V semiconductor quantum wells and superlattices are components in systems used for space applications. For example, focal plane arrays fabricated from GaAs related multiple quantum wells for long wavelength application is a sensor used in space for various applications. The prolonged operation of such devices in space environment may results in degradation due to electron, proton, neutron and gamma-ray radiation. Thus, it is desired to study multiple quantum well structures that form the basis of long wavelength infrared detectors, under the influence of various radiation effects. In this article, we present photoluminescence (PL) measurements of interband transitions in InGaAs/AlGaAs multiple quantum wells before and after fast neutron irradiation. We will provide possible explanations to the degradation of interband transition as the irradiation dose is increased. The degradation of the interband transition was judged from the dramatic reduction of the normalized integrated area as well as the shift in the peak position energy of the PL spectra. EXPERIMENT: The multiple quantum well (MQW) structure used in the present study was grown by the molecular-beam epitaxy technique on a semi-insulating GaAs substrate. The wafer consists of 50 periods of 75 A thick Ino.o7Gao. 93As well and 100 A thick A10.4Gao.6 As barrier. The well 525 Mat. Res. Soc. Symp. Proc. Vol. 607 @ 2000 Materials Research Society
regions were Si-doped {[Si] = 2x1018 cm3 . The uniformity of the wafer was determined from the peak position of the intersubband transition measurements to be within less than 0.5 meV in samples cut from the center and
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