Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 24
Filter
1.
Med. intensiva (Madr., Ed. impr.) ; 35(4): 232-235, mayo 2011.
Article in Spanish | IBECS | ID: ibc-92795

ABSTRACT

Resumen Aunque una especialidad joven en comparación con otras disciplinas médicas, laMedicina Intensiva ocupa en la actualidad un papel clave en el proceso asistencial de muchospacientes. La experiencia ha demostrado que, para ofrecer una asistencia de calidad a lospacientes críticos, es necesario disponer de profesionales con una formación específica enMedicina Intensiva. En Europa se han dado pasos importantes hacia la homogeneización delos programas formativos de los distintos Estados miembros, pero es necesario dar un paso más,que es la creación de una especialidad primaria de Medicina Intensiva. La atención al enfermocrítico debe ser liderada por especialistas que hayan recibido una formación específica y completa,y posean las competencias profesionales necesarias para prestar una asistencia de lamáxima calidad a sus pacientes. El futuro de la especialidad presenta retos que habrá queafrontar con determinación, teniendo como objetivo principal satisfacer las necesidades de lapoblación (AU)


Abstract Although Intensive Care Medicine is a young specialty compared with other medicaldisciplines, it currently plays a key role in the process of care for many patients. Experiencehas shown that professionals with specific training in Intensive Care Medicine are needed toprovide high quality care to critically ill patients. In Europe, important steps have been takentowards the standardization of training programs of the different member states. However, itis now necessary to take one more step forward, that is, the creation of a primary specialtyin Intensive Care Medicine. Care of the critically ill needs to be led by specialists who havereceived specific and complete training and who have the necessary professional competencesto provide maximum quality care to their patients. The future of the specialty presents challengesthat must be faced with determination, with the main objective of meeting the needsof the population (AU)


Subject(s)
Humans , Critical Care/trends , Medicine/trends , Intensive Care Units , Education, Medical/trends
2.
Med Intensiva ; 35(4): 232-5, 2011 May.
Article in Spanish | MEDLINE | ID: mdl-21354658

ABSTRACT

Although Intensive Care Medicine is a young specialty compared with other medical disciplines, it currently plays a key role in the process of care for many patients. Experience has shown that professionals with specific training in Intensive Care Medicine are needed to provide high quality care to critically ill patients. In Europe, important steps have been taken towards the standardization of training programs of the different member states. However, it is now necessary to take one more step forward, that is, the creation of a primary specialty in Intensive Care Medicine. Care of the critically ill needs to be led by specialists who have received specific and complete training and who have the necessary professional competences to provide maximum quality care to their patients. The future of the specialty presents challenges that must be faced with determination, with the main objective of meeting the needs of the population.


Subject(s)
Critical Care/trends , Medicine/trends , China , Education, Medical/standards , Europe , Forecasting , Health Services Needs and Demand , Spain
5.
Med. intensiva (Madr., Ed. impr.) ; 33(4): 153-160, mayo 2009. graf, tab
Article in Spanish | IBECS | ID: ibc-73135

ABSTRACT

Objetivo. Estudiar el uso de la ventilación no invasiva (VNI) en la insuficiencia respiratoria aguda, en las unidades de cuidados intensivos (UCI) de España. Métodos. Se realizó una encuesta a 254 UCI. Al final de ésta se invitó a participar en un estudio multicéntrico retrospectivo, y proporcionar información detallada sobre pacientes ventilados. Resultados. Contestaron 123 UCI; 119 utilizaban la VNI, de manera muy variable. En la enfermedad pulmonar obstructiva crónica (EPOC), la VNI fue de primera elección en el 89% de las unidades; en el edema agudo de pulmón (EAP), el 79%; en la insuficiencia respiratoria tras la extubación, el 53%; en la neumonía, el 53%, y en el síndrome de distrés respiratorio agudo (SDRA), el 17%. Su utilización en la EPOC fue ocasional o nula en el 11% de las unidades, y en el EAP, en el 21%. 18 hospitales enviaron información de 432 pacientes ventilados, de los que 232 (54%) recibieron VNI como primera elección. La neumonía o el SDRA fueron factores independientes en relación con el fracaso de la VNI (odds ratio ajustada [ORa] = 5,71; intervalo de confianza [IC] del 95%, 1,83-17,8; p = 0,003). La admisión en una unidad que ventilara de forma no invasiva a más de 50 pacientes/año (ORa = 0,22; IC del 95%, 0,07-0,63; p = 0,005) y una mayor razón PaO2/FIO2 tras una hora de ventilación (ORa = 0,98 por punto; IC del 95%, 0,97-0,99; p < 0,001) fueron factores protectores. Conclusiones. La VNI es ampliamente utilizada en las UCI de España, pero es posible que siga estando infrautilizada en la EPOC y el EAP. El diagnóstico de neumonía o SDRA fue un factor independiente en relación con el fracaso. Ventilar a más de 50 pacientes/año y una mayor PaO2/FIO2 tras una hora fueron factores protectores(AU)


Objectives. Study the use of non-invasive ventilation (NIV) in patients with acute respiratory failure in intensive care units (ICUs) in Spain. Methods. A questionnaire was sent to 254 ICUs, after which, they were invited to participate in a multicenter, retrospective study, providing detailed information on ventilated patients. Results. Answers were received from 123 hospitals. Of these, 119 used NIV, although its use varied greatly. NIV is the treatment of choice in 89% of the units for chronic obstructive pulmonary disease (COPD), in 79% for acute pulmonary edema (APE), in 53% for postextubation failure, in 53% for pneumonia 53%, and in 17% for acute respiratory distress syndrome (ARDS). It was used occasionally in COPD in 11% of the units, and in 21% of the units for APE. Eighteen hospitals provided additional information on 432 ventilated patients, 232 (54%) of whom received NIV as first line therapy. Presence of pneumonia or acute respiratory distress syndrome (ARDS) was an independent predictive factor of NIV failure (ORa = 5.71; CI 95%, 1.83-17.8; p = 0.003). Admission in a unit with experience in NIV in > 50 patients/year (ORa = 0.22; CI 95%, 0.07-0.63; p = 0.005) and a higher PaO2/FiO2 ratio after one hour of ventilation (ORa = 0.98 per point; CI 95%, 0.97-0.99; p < 0.001) were protector factors. Conclusions. In Spain, NIV is widely used but it may continue to be underused in COPD and APE. The diagnosis of pneumonia or ARDS was an independent predictive risk factor. Admission in an ICU with NIV in more than 50 patients/year also have higher PaO2/FiO2 ratio after one hour of ventilation were predictive factors of success(AU)


Subject(s)
Humans , Male , Female , Middle Aged , Aged , Respiratory Insufficiency/therapy , Respiration, Artificial/methods , Intensive Care Units , Retrospective Studies , Socioeconomic Survey
6.
Nanoscale Res Lett ; 4(8): 878-887, 2009 May 09.
Article in English | MEDLINE | ID: mdl-20596285

ABSTRACT

We present results derived from continuous and localized 35 keV (55)Mn(+) ion implantations into ZnO. Localized implantations were carried out by using self-ordered alumina membranes as masks leading to ordered arrays of implanted volumes on the substrate surfaces. Defects and vacancies in the small implantation volumes of ZnO were generated due to the implantation processes besides the creation of new phases. Rapid thermal annealing was applied in the case of continuous implantation. The samples were characterized by HRSEM, GIXRD, Raman spectroscopy and RBS/C. Magnetic characterization of the samples pointed out appreciable differences among the samples obtained by the different implantation methods. This fact was mainly attributed to the different volume/surface ratios present in the implanted zones as well as to the increase of Mn atom concentrations along the grain frontiers in the nanostructured surfaces. The samples also showed a ferromagnetic transition phase at temperature value higher than room temperature.

7.
Med. intensiva (Madr., Ed. impr.) ; 32(2): 71-77, mar. 2008. ilus, tab
Article in Es | IBECS | ID: ibc-63851

ABSTRACT

Objetivo. Demostrar que el consenso interdisciplinar mejora la calidad del trabajo en la Unidad de Cuidados Intensivos (UCI), evitando exploraciones radiológicas rutinarias innecesarias, planteándose una monitorización de los resultados para mantener este bajo porcentaje de peticiones. Diseño. Ciclo de mejora de calidad asistencial. Ámbito. UCI de 18 camas de carácter polivalente. Pacientes. Pacientes ingresados en la UCI en el periodo de un mes, durante el cual se hizo un muestreo aleatorio sistemático. Intervenciones. Establecimiento de un protocolo consensuado de petición de radiografías de tórax portátiles (RTP) rutinarias. Tras comprobar el exceso de RTP siguiendo estos criterios, se acordó con todos los intensivistas su aplicación. Cinco años después se volvió a valorar el grado de incumplimiento y se incluyó un calendario de monitorizaciones para evitar la vuelta al exceso de solicitudes no justificadas. Además se introdujo un sistema de petición consensuado entre dos intensivistas, de manera que todas las RTP programadas para cada día se solicitaban por parte de dos intensivistas, atendiendo a los mencionados criterios. Variable. Peticiones que incumplen el protocolo de RTP programada. Resultados. En 1997, el grado global de incumplimiento era del 16,9%. Tras reducirlo al 6,1%, la falta de control posterior llevó a que en 2003 fuese del 27,6%. Los pacientes estables con cardiopatía isquémica (44,4% y 53,8% de todos los incumplimientos en esos dos años) constituyen el grueso de las indicaciones inadecuadas. El uso de un modelo de solicitud que requiere del consenso de dos intensivistas consiguió una reducción del incumplimiento al 2,5% en 2003. El calendario de monitorización ha permitido seguir en el tiempo el grado de cumplimiento y detectar la relajación en la prescripción. Conclusiones. Las RTP innecesarias pueden reducirse fácilmente incidiendo sobre los pacientes clínicamente estables. La obligación de justificar una petición rutinaria (consenso entre intensivistas) permite disminuir el número de peticiones de RTP. La monitorización periódica es la herramienta final para el éxito del ciclo de mejora


Purpose. To demonstrate that interdisciplinary consensus improves the quality of work in the daily Intensive Care Unit (ICU), thus avoiding unnecessary routine x-ray examinations. We propose to monitor the results to maintain this low percentage of requests for x-rays. Design. Cycle of improvement in care quality. Setting. An 18-bed polyvalent ICU. Patients. A random sample of patients admitted in ICU during one month. Interventions. Establishment of basic agreed on protocol for routine chest portable x-ray (CPR) indications. After assessing the excessive amount of CPR according to those criteria, all intensivists accepted their application. Five years later, a second assessment of the degree of non-compliance was carried out and a monitoring schedule was established in order to avoid making unnecessary CPR again. Furthermore, a consensus between two intensivists was considered obligatory before a CPR request. Accordingly, all non-urgent CPR forms were signed by two intensivists, following the mentioned clinical criteria. Variable. Unsuitable portable chest x-ray indications. Results. In 1997, the overall non-compliance rate (ONCR) was 16.9%. After reducing it to 6.1%, lack of follow-up led to a non-compliance rate of 27.6% in 2003. Stable patients with uncomplicated ischemic heart disease (44.4% in 1997 and 53.8% in 2003) accounted for most of the inadequate ONCR indications. By using the consensus system for requesting routine portable x-rays that required the agreement of two intensivists achieved a reduction of non-compliance to 2.5% in 2003. The monitoring schedule designed has made it possible to follow the time of compliance degree and detect relaxation in the prescriptions. Conclusions. Unnecessary CPR can be easily reduced stressing our control in clinically stable patients. The requirement to justify a routine request (agreement between intensivists) makes it possible to decrease the number of CPRs. Periodic monitoring is the definitive tool for a successful improvement cycle


Subject(s)
Humans , Radiography, Thoracic , Intensive Care Units/organization & administration , 34002 , Cost Savings/trends , Mass Screening , Patient Selection
8.
Med Intensiva ; 32(2): 71-7, 2008 Mar.
Article in Spanish | MEDLINE | ID: mdl-18275754

ABSTRACT

PURPOSE: To demonstrate that interdisciplinary consensus improves the quality of work in the daily Intensive Care Unit (ICU), thus avoiding unnecessary routine x-ray examinations. We propose to monitor the results to maintain this low percentage of requests for x-rays. DESIGN: Cycle of improvement in care quality. SETTING: An 18-bed polyvalent ICU. PATIENTS: A random sample of patients admitted in ICU during one month. INTERVENTIONS: Establishment of basic agreed on protocol for routine chest portable x-ray (CPR) indications. After assessing the excessive amount of CPR according to those criteria, all intensivists accepted their application. Five years later, a second assessment of the degree of non-compliance was carried out and a monitoring schedule was established in order to avoid making unnecessary CPR again. Furthermore, a consensus between two intensivists was considered obligatory before a CPR request. Accordingly, all non-urgent CPR forms were signed by two intensivists, following the mentioned clinical criteria. VARIABLE: Unsuitable portable chest x-ray indications. RESULTS: In 1997, the overall non-compliance rate (ONCR) was 16.9%. After reducing it to 6.1%, lack of follow-up led to a non-compliance rate of 27.6% in 2003. Stable patients with uncomplicated ischemic heart disease (44.4% in 1997 and 53.8% in 2003) accounted for most of the inadequate ONCR indications. By using the consensus system for requesting routine portable x-rays that required the agreement of two intensivists achieved a reduction of non-compliance to 2.5% in 2003. The monitoring schedule designed has made it possible to follow the time of compliance degree and detect relaxation in the prescriptions. CONCLUSIONS: Unnecessary CPR can be easily reduced stressing our control in clinically stable patients. The requirement to justify a routine request (agreement between intensivists) makes it possible to decrease the number of CPRs. Periodic monitoring is the definitive tool for a successful improvement cycle.


Subject(s)
Guideline Adherence/statistics & numerical data , Intensive Care Units/standards , Radiography, Thoracic/statistics & numerical data , Humans , Quality Control
9.
Ann Trop Med Parasitol ; 99(2): 125-30, 2005 Mar.
Article in English | MEDLINE | ID: mdl-15814031

ABSTRACT

Although visceral leishmaniasis is often fatal in the developing world, Leishmania-attributable deaths in Europe are relatively rare and nowadays almost always linked to HIV infection. In Spain, however, a HIV-negative man with a history of chronic obstructive pulmonary disease and prednisone treatment was recently hospitalized because of hypotension and asthenia. Although the patient was afebrile, a bone-marrow aspirate, collected after thrombo- and leuco-cytopenia had been observed, was found to contain huge numbers of amastigotes. A course of antileishmanial treatment with meglumine antimoniate was initiated but the patient went into refractory shock and died within 6 h. The significance of this case, in terms of the routine investigation and treatment of immunosuppressed patients who may have leishmaniasis, is discussed.


Subject(s)
Bone Marrow Diseases/immunology , HIV Seronegativity/immunology , Immunocompromised Host , Leishmaniasis, Visceral/immunology , Antiprotozoal Agents/therapeutic use , Bone Marrow/parasitology , Bone Marrow Diseases/drug therapy , Bone Marrow Diseases/parasitology , Fatal Outcome , Glucocorticoids/adverse effects , Humans , Hypotension/complications , Hypotension/drug therapy , Leishmaniasis, Visceral/complications , Leishmaniasis, Visceral/drug therapy , Male , Meglumine/therapeutic use , Meglumine Antimoniate , Middle Aged , Organometallic Compounds/therapeutic use , Prednisone/adverse effects , Pulmonary Disease, Chronic Obstructive/complications , Pulmonary Disease, Chronic Obstructive/drug therapy
12.
Med. intensiva (Madr., Ed. impr.) ; 28(1): 26-28, ene. 2004. ilus
Article in Es | IBECS | ID: ibc-29419

ABSTRACT

Se sabe que la diabetes mellitus se acompaña de una serie de alteraciones metabólicas, cardiovasculares y de las funciones neuronales. La cetoacidosis diabética es una de las 3 complicaciones potencialmente mortales de la diabetes mellitus junto a la hipoglucemia y el coma hiperosmolar, y aparece fundamentalmente en pacientes con diabetes mellitus tipo 1 (DM1) o insulinodependientes. Por otra parte, es conocido que algunos pacientes con cetoacidosis diabética presentan una temperatura corporal baja, incluso cuando hay una infección. Sin embargo, no es frecuente que coexista con una situación clínica de hipotermia grave. Presentamos el caso de un paciente que ingresó en nuestra unidad de cuidados intensivos en coma, con cetoacidosis diabética e hipotermia grave (27,6 °C). Revisamos la fisiopatología y el tratamiento de ambas complicaciones cuya asociación es poco frecuente en la práctica clínica habitual (AU)


Subject(s)
Adult , Male , Humans , Diabetic Ketoacidosis/complications , Hypothermia/etiology , Hypothermia/therapy , Diabetes Mellitus, Type 1/complications
13.
Med. intensiva (Madr., Ed. impr.) ; 28(1): 11-17, ene. 2004. ilus, tab
Article in Es | IBECS | ID: ibc-29416

ABSTRACT

Fundamento. El traslado para la realización de angioplastia primaria puede suponer un retraso y un riesgo añadido que limite los beneficios de ésta como estrategia de reperfusión en pacientes con infarto agudo de miocardio. El objetivo del presente estudio ha sido analizar los tiempos invertidos en cada etapa en la realización de la angioplastia primaria mediante el traslado desde un hospital sin hemodinámica y la seguridad en el transporte en la práctica clínica habitual. Pacientes y método. Estudio prospectivo observacional de los pacientes que, tras consultar en nuestra área de urgencias con un infarto agudo de miocardio, fueron trasladados para angioplastia primaria a nuestro hospital de referencia entre julio de 2000 y enero de 2002. Se analizan los intervalos desde el inicio de los síntomas hasta la apertura de la arteria causante del infarto y las complicaciones en el traslado. Resultados. Se trasladó a 137 pacientes, de los que regresaron 117. Se realizó angioplastia primaria a 111 pacientes. Los tiempos observados en minutos fueron (expresados como mediana [percentiles 25-75]): inicio de los síntomas llegada al hospital, 100 (60-161); llegada al hospital-diagnóstico, 15 (2,5-25); diagnóstico-traslado 25, (20-40); traslado en ambulancia, 20 (15-20); llegada al hospital de referencia-apertura del vaso, 24 (10-30); apertura del vaso-flujo TIMI III, 20 (0-25); y global, diagnóstico-apertura del vaso 70 (55-85). Tan sólo en 2 pacientes el tiempo desde el diagnóstico hasta la apertura del vaso fue superior a 120 min y en el 84 por ciento de los casos fue inferior a 90 min. No hubo complicaciones graves durante el traslado. Conclusiones. En nuestro medio el traslado para angioplastia primaria desde un hospital sin hemodinámica es seguro y supone un retraso que está dentro de los límites recomendados. El mayor retraso se observó en el intervalo desde el inicio de los síntomas hasta la llegada al hospital. Una vez diagnosticado el paciente, el mayor retraso se produjo en el intervalo desde el diagnóstico hasta la llegada de la ambulancia para el traslado. (AU)


Subject(s)
Humans , Myocardial Infarction/therapy , Transportation of Patients/methods , Angioplasty/methods , Prospective Studies , Intensive Care Units , Ambulances/supply & distribution
15.
Ortod. esp. (Ed. impr.) ; 43(1): 25-30, ene. 2003. ilus
Article in Es | IBECS | ID: ibc-21607

ABSTRACT

El tratamiento de las mordidas abiertas es complicado debido a la dificultad para diferenciar los factores dentoalveolares y esqueléticos dentro del patrón de crecimiento del paciente. Las mordidas abiertas de origen dentoalveolar en dentición mixta pueden corregirse de forma espontánea una vez eliminado el hábito que la produce. En los casos leves y moderados debido a factores esqueléticos, se debe esperar hasta finalizada la pubertad para evitar la extrusión de las zonas posteriores por la mecanoterapia. En los casos más graves se realizará la cirugía ortognática en la edad adulta. Los objetivos de todo tratamiento deben incluir la corrección de la inclinación de los planos oclusales y el enderezamiento de los molares posteriores. La técnica desarrollada por Kim, 'Multiloop Edgewise Archwire' (MEAW) se creó para alcanzar estos objetivos.A continuación presentaremos un caso de mordida abierta en un paciente con clase III tratado con la técnica modificada de Kim (AU)


Subject(s)
Adult , Female , Humans , Open Bite/therapy , Orthodontics, Corrective/methods , Treatment Outcome , Activator Appliances , Orthodontic Appliances
17.
Med. intensiva (Madr., Ed. impr.) ; 26(7): 349-355, sept. 2002. graf, tab
Article in Es | IBECS | ID: ibc-16636

ABSTRACT

Fundamento. El fallo renal agudo (FRA) se asocia frecuentemente al síndrome de disfunción multiorgánica (SDMO) en los pacientes críticos. El uso de técnicas continuas de sustitución renal (TCSR) fue descrito por primera vez hace unos 20 años. Analizamos aquí nuestra experiencia valorando los factores pronósticos y la evolución clínica de los pacientes. Pacientes y métodos. Se realizó un estudio descriptivo, observacional y retrospectivo de todos los pacientes críticos con FRA tratados con TCSR, durante el período comprendido entre enero de 1996 y diciembre de 2000. Se recogieron datos demográficos y clínicos, y se realizó un análisis estadístico descriptivo, comparativo y de regresión logística para el estudio de los factores de riesgo relacionados con la mortalidad. Resultados. Fueron evaluados 73 pacientes. La media de edad fue 61 años (intervalo, 17-79), el 62 per cent eran varones, el APACHE II medio fue de 24 (8) y el SAPS II medio fue de 65 (16). La mortalidad global alcanzó el 86,3 per cent. Mediante regresión logística el riesgo de muerte fue más alto en los pacientes con complicaciones relacionadas con la técnica (OR = 2,00; IC del 95 per cent, 1,763-250,0; p = 0,016) y más bajo en pacientes con diuresis residual mayor (OR = 0,995; IC del 95 per cent, 0,990-0,999; p = 0,028). Conclusiones. La mortalidad del FRA que acompaña al SDMO sigue siendo elevada. Las TCSR pueden ser útiles en estos pacientes. En nuestra unidad la ausencia de complicaciones relacionadas con la técnica y la mayor diuresis residual se relacionan con una menor mortalidad. (AU)


Subject(s)
Adolescent , Adult , Aged , Female , Male , Middle Aged , Humans , Acute Kidney Injury/therapy , Renal Replacement Therapy/mortality , Risk Factors , Retrospective Studies , Mortality , Acute Kidney Injury/complications , Prognosis
18.
Intensive Care Med ; 27(11): 1718-28, 2001 Nov.
Article in English | MEDLINE | ID: mdl-11810114

ABSTRACT

CONTEXT: In patients with hypoxemic acute respiratory failure (ARF), randomized studies have shown noninvasive positive pressure ventilation (NPPV) to be associated with lower rates of endotracheal intubation. In these patients, predictors of NPPV failure are not well characterized. OBJECTIVE: To investigate variables predictive of NPPV failure in patients with hypoxemic ARF. DESIGN: Prospective, multicenter cohort study. SETTING: Eight Intensive Care Units (ICU) in Europe and USA. PATIENTS: Of 5,847 patients admitted between October 1996 and December 1998, 2,770 met criteria for hypoxemic ARF. Of these, 2,416 were already intubated and 354 were eligible for the study. RESULTS: NPPV failed in 30% (108/354) of patients. The highest intubation rate was observed in patients with ARDS (51%) or community-acquired pneumonia (50%). The lowest intubation rate was observed in patients with cardiogenic pulmonary edema (10%) and pulmonary contusion (18%). Multivariate analysis identified age > 40 years (OR 1.72, 95% CI 0.92-3.23), a simplified acute physiologic score (SAPS II) > or = 35 (OR 1.81, 95% CI 1.07-3.06), the presence of ARDS or community-acquired pneumonia (OR 3.75, 95% CI 2.25-6.24), and a PaO2:FiO2 < or = 146 after 1 h of NPPV (OR 2.51, 95% CI 1.45-4.35) as factors independently associated with failure of NPPV. Patients requiring intubation had a longer duration of ICU stay ( P < 0.001), higher rates of ventilator-associated pneumonia and septic complications ( P < 0.001), and a higher ICU mortality ( P < 0.001). CONCLUSIONS: In hypoxemic ARF, NPPV can be successful in selected populations. When patients have a higher severity score, an older age, ARDS or pneumonia, or fail to improve after 1 h of treatment, the risk of failure is higher.


Subject(s)
Positive-Pressure Respiration/methods , Respiratory Insufficiency/therapy , Acute Disease , Adolescent , Adult , Aged , Aged, 80 and over , Chi-Square Distribution , Female , Humans , Intubation, Intratracheal , Italy , Male , Middle Aged , Predictive Value of Tests , Prospective Studies , Risk Factors , Spain , Statistics, Nonparametric , Tennessee , Treatment Failure
20.
Appl Opt ; 31(10): 1606-11, 1992 Apr 01.
Article in English | MEDLINE | ID: mdl-20720795

ABSTRACT

The refractive index n and the absorption coefficient a of radio frequency sputtered CuGaSe(2) and CuInSe(2) thin films were obtained by means of transmissivity (T) and reflectivity (R) measurements at normal incidence. The optical properties were determined from the rigorous expressions for the transmission and the reflection in an air/film/(glass)substrate/air multilayer system. The solutions to this system of equations are not unique, and the physically meaningful solution is identified by trying different thicknesses in the numerical approach. Usually, nonacceptable n dispersion curves are found for all thicknesses. To be able to obtain a good n dispersion curve and, therefore, a correct absorption coefficient, we propose a simple modification of the equations for R and T through a factor called the coherence factor (CF). Because of the surface roughness and the nonuniformity of n and alpha, the light rays that reflect internally in the interface between the substrate and the film have a random difference in opt cal path. The CF accounts for this effect. This modification leads to an unambiguous and accurate determination of the optical properties and thickness of thin films for all wavelengths where transmission is not negligible. The CF is shown to be greatly dependent on the thickness of the film. This method can be used even when the R and T spectra do not have interference fringes. This method is applied successfully to the optical analyses, in the 0.4-2.5-mum wavelength range, of CuInSe(2) and CuGaSe(2) ternary chalcopyrite thin films deposited onto glass substrates by radio-frequency sputtering.

SELECTION OF CITATIONS
SEARCH DETAIL
...