Oludurotimi O. Adetunji

High-temperature solution growth of Cr2+ : CdSe for tunable mid-IR laser application

Solid-state tunable laser sources in the mid-IR region have been recently investigated for their potential in remote sensing applications. Room temperature lasers based on single crystals of chromium-doped CdSe are particularly interesting due to their broad band tunability beyond 2 lm spectral region. In this study, we have grown doped single crystals by the high-temperature gradient freezing solution technique, using selenium as the solvent. Crystals of 1.2 cm in diameter and up to 7 cm long, cracks and precipitates free could be obtained. The e!ective segregation coe

Compositional variations and phase stability during horizontal Bridgman growth of AgGaTe2 crystals

cient of Cr2‘ ions along the ingot was evaluated. Room temperature emission lifetime values of 3.0}4.5 ls were measured. ( 2000 Published by Elsevier Science B.V. All rights reserved.

Au/CdZnTe/CdS m-i-n detectors fabricated by sputtering technique

AbstractWe report the synthesis and growth of large, crack-free AgGaTe 2 single crystals by the horizontal Bridgmantechnique. The ingots were nearly stoichiometric and consisted entirely of single-phase material, with somecompositionalvariationsofthemetalcomponents.Thepresenceofmicroprecipitateswasobservedinthefast-cooledsamples.Theeffectsofthecompositionalvariationsonbandgap,absorptioncoefficient,meltingpointandelectricalresistivityalongthelengthoftheingotarereported.r 2002ElsevierScienceB.V.Allrightsreserved. PACS: 81.10;61.66.F;81.70.P;61.10;65.70;72.15.EKeywords: A1.Absorption;A1.Thermalanalysis;A2.Bridgmantechnique;A2.Growthfrommelt 1. IntroductionTernarychalcopyritesoftheclassI–III–VI 2 areknown infrared nonlinear optical materials [1–3].In spite of its potential application for secondharmonicgenerationandopticalparameteroscil-lation,AgGaTe 2 hasreceivedlittleattention[4–6].Until recently, growth of large AgGaTe 2 singlecrystalswasthemainhindranceformanyapplica-tions. Recently, Schunemann et al. [7] firstreported the growth of large crack-free singlecrystalsofAgGaTe

Thermal diffusion of Cr2+ in bulk ZnSe

The electrical and detection properties of Au/CdZnTe/CdS (m- i-n) gamma-ray and x-ray detectors, fabricated by sputtering technique, have been studied. The CdZnTe crystal was grown by the High Pressure Bridgman method. Current-voltage measurements show that the leakage current is reduced by an order of magnitude when the m-i-n detector is reversed biased. This is due to increased contact barriers, which produced effective blocking contacts. An energy resolution of 3.6 percent for the 59.6 keV line of 241Am was obtained in the reverse bias, with almost no energy resolution for the forward bias due to excessive leakage current.