Improved photoluminescence characteristics of order-disorder AlGaInP quantum wells at room and elevated temperatures

Abstract

Photoluminescence decay dynamics in an InGaN/GaN/AlGaN single quantum wellA set of nominally undoped CuPt-B type ordered (Al x Ga 1Àx ) 0.5 In 0.5 P quantum-wells with disordered (Al 0.7 Ga 0.3 ) 0.5 In 0.5 P barriers were grown and characterized using transmission electron microscopy and photoluminescence spectroscopy. Such structures are potentially beneficial for light emitting devices due to the possibility of greater carrier confinement, reduced scattering into the indirect valleys, and band-offset adjustment beyond what is possible with strain and composition. Furthermore, the possibility of independently tuning the composition and the order-parameter of the quantum-well allows for the decoupling of the carrier confinement and the aluminum content and aids in the identification of carrier loss mechanisms. In this study, sharp order-disorder interfaces were achieved via the control of growth temperature between 650 C and 750 C using growth pauses. Improved high-temperature (400 K) photoluminescence intensity was obtained from quantum-wells with ordered Ga 0.5 In 0.5 P as compared to disordered Ga 0.5 In 0.5 P due to greater confinement. Additionally, in the ordered samples with a higher Al/Ga ratio to counter the band-gap reduction, the photoluminescence intensity at high temperature was as bright as that from conventional disordered heterostructures and had slightly improved wavelength stability. Room-temperature time-resolved luminescence measurements indicated a longer radiative lifetime in the ordered quantum-well with reduced scattering into the barrier. These results show that in samples of good material quality, the property controlling the luminescence intensity is the carrier confinement and not the presence of ordering or the aluminum content. V C 2015 AIP Publishing LLC. [http://dx.

Understanding semiconductor nanostructures via advanced electron microscopy and spectroscopy

“…Atomic ordering in ternary or quaternary semiconductors has been proven to have a dramatic effect on electronic band structure [ 109 , 110 , 111 ]. Several studies have theoretically and experimentally shown the difference of the physical properties between ordered and disordered structures such as InGaAs, GaAsSb, InGaP [ 112 ], AlInP [ 113 ] and AlGaInP [ 114 ] Previously, the use of scanning tunneling microscopy (STM) to identify atomic ordering has been reported [ 115 ]. Conventional HRTEM imaging associated with diffraction pattern methods also can provide information about the atomic ordering [ 116 , 117 , 118 , 119 , 120 ].…”

Recombination activity of threading dislocations in GaInP influenced by growth temperature

“…22,27 Recent time-resolved and continuous-wave photoluminescence measurements from similarly designed quantum-well samples grown in the same MOCVD chamber also showed a doubling in at room temperature with no reduction in emission intensity as the GaInP growth temperature was reduced from 750 °C (disordered) to 650 °C (ordered). 19 As there was no change in the CL intensity between 725 °C and 675 °C in this study, we interpreted this as a doubling of without much impact from a relatively longer . This would lead to a doubling in ≈ but only a slight decrease in the quantum efficiency that is proportional to ( + ) ⁄ and is close to 0.9-1 for both growth temperatures.…”

“…The integrated CL intensities from the samples grown at 725 °C and 675 °C are very similar, in line with previous photoluminescence results with dislocation-free order/disorder quantum wells. 19 However, further reduction of the growth temperature of the quantum well to 625 °C results in a decline in CL intensity of 30%.…”

“…In previous work on ordered AlGaInP quantum wells, which are known to have a higher order parameter than GaInP, was seen to increase by nearly an order of magnitude at room temperature compared to the disordered case. 19 Approximate values of = 1, 2, and 5 ns were inferred for the samples grown at 725, 675, and 625 °C, respectively, based on the intensity results and lifetime results 19 . This is consistent with the CL intensity measurements assuming a constant = 11-13 ns across the samples.…”

Экспериментальные исследования влияния эффектов атомного упорядочения в эпитаксиальных твердых растворах Ga-=SUB=-x-=/SUB=-In-=SUB=-1-x-=/SUB=-P на их оптические свойства

“…Периодические структуры таких включений могут об-разовывать сверхрешетки, состоящие из квантовых ям, проводов или точек. Явления спонтанного возникнове-ния наноструктур создают основу для новой технологии получения упорядоченных массивов неоднородностей -базу для опто-и микроэлектроники нового поколе-ния [1][2][3].…”