Wavelength shifting in InP based ultra-thin quan[um

InP based ultra-thin quan[um well is changed from a square well, with quantum well infrared photodetector via rapid sharp interfaces, to an error-function shaped well, thermal annealing with a corresponding change in the confined energy 1cvcIs[3,4]. This tunability is of interest to IR QWIPS such as the detector photoresponse and absolute rcsponsivity. by gas source molecular beam epitaxy (GSMBE) system on semi-insulating (001) InP substrates. [5]. The p-type structure consisted of 30 periods of IOA Institute of Microstructural Sciences, National Be center doped (3x10'8~m-3) In053Ga0,47As Research Council, Canada K1 A OR6 quantum wells (QWS) and 500A Be doped (1x1017 CIII-J) lnP barriers sandwiched between 5000A Be Abstract-We have demonstrated red-shifting of doped (3x 1018 cm-~) In0,s3 G~,47As contacts on InP the wavelength response of a bound-to-continuum substrate. In all studies, prior to anneding,, the p-type ultra-thin InGaAs/InP quantum well samples are first degreased in trichloromethane, infrared photodetector after growth via rapid acetone, and methanol followed by a light surface thermal annealing. Compared to the as-grown etch using NH 4 0H. Then, a ISOOA SiOz detector, the peak spectral response of the encapsulant is deposited by plasma enhanced annealed detector was shifted to longer chemical vapor deposition. Rapid thermal wavelength without any major degradation in the annealing is performed in an AET RTA reactor responsivity characteristics. Thus, the post-with 10 seem of N 2 flowing. The temperature is growth control of InGaAs/InP quantum well stabilized at 200 " C prior to the high temperature composition profiles by rapid thermal annealing anneal. The material quality and optical properties offers unique opportunities to fine tune various of the as-grown and annealed lnGaAsflnP MQW aspects of a photodetector's response. samples arc investigated using cross-sectional transmission electron microscopy (TEM), and 1. INTRODUCTION photolurnincscence measurements (PL). Cross-One of the distinct advantages of the quantum well sectional transmission electron microscopy study approach is the ability to produce multi-band or was pcrforrncd at 120KV on a Phillips CM 12 multi-color detectors, which arc desirable for future microscope. 6K PL measurements were performed high-performance IR systems [ 1]. In all cases, the with 514nnl excitation from an argon ion laser. The detection wavelengths are chosen prior to growth by PI. was dispersed by a lrn single grating designing the layer struc(urc accordingly. spcctrorncter and then detected with a Gc detector. Interdiffusion offers the flexibility to modify the properties of the materials after growth. It is The cross-sectioned TEM micrographs …