Title

Análisis de las características de celdas solares basadas en heteroestructuras ITO/n-Si.

Author

GUILLERMO RUIZ TABOADA

Contributor

OLEKSANDR MALIK (Thesis Adviser)

CARLOS ZUÑIGA ISLAS (Thesis Adviser)

Access level

Open Access

Summary or description

This work is focused on a theoretical study of an experimental solar cell, fabricated on a tin-doped indium oxide-silicon (ITO-Si) heterostructure. A 10 omega-cm resistivity silicon substrate was used. The main characteristics of the p-n and Schottky barrier physical models were analyzed. The application limits of each model were clearly defined. Based on the previous analysis, It was found that the experimental structure can be considered as a surface inversion p+-n junction and a theoretical model for inversion p-n ITO-nSi solar cells has been developed. This model is able to describe the behavior of such structure in an accurate way. Based on a p+-n model, theoretical calculations are presented. They show an

excellent agreement with the experimental results. Such agreement gave us the possibility to calculate the photovoltaic characteristics of hypothetical ITOnSi solar cells. It was found that the use of silicon substrates with resistivities lower than 10 omega-cm improves the cell efficiency. Moreover, it is shown that using substrates with resistivities lower than 1 omega–cm, the p-n model is not applicable. With the purpose of obtaining similar p-n structures as those obtained with ITO-Si, and based on the knowledge of the shallow and low resistive junctions formed by rapid thermal processes (RTP); p-n solar cells were fabricated by using this technique and a solid dopant source (spin on dopant SOD). The best characteristics achieved by these cells were below the theoretical values predicted by p-n model. A fabrication process depuration is proposed as a future work

En este trabajo se realiza el estudio teorico de una celda solar experimental basada en la heteroestructura ITO-Si fabricada en un substrato de silicio cristalino con resistividad de 10 omega–cm. Se realiza un analisis teorico de las principales caracteristicas de los modelos fisicos p-n y de barrera Schottky, definiendo claramente los limites de aplicacion de cada uno. Con base en esto, se encuentra que la celda experimental puede ser considerada como una union p+-n por inversion superficial del substrato y se desarrolla un modelo fisico y matematico capaz de describir de manera precisa el comportamiento de esta estructura experimental. Se presentan calculos teoricos con resultados que muestran una concordancia excelente con los valores experimentales, lo cual permite visualizar una mejora en las figuras de merito de la estructura mediante el empleo de substratos con resistividad menor a los 10 omega–cm. Se encuentra que para el caso de substratos con resistividad menor a 1 omega–cm, el modelo p-n por inversion superficial del substrato ya no sera aplicable. En un esfuerzo por obtener estructuras p-n similares a las logradas con las celdas ITO-Si, se fabricaron celdas solares en substratos de silicio cristalino basadas en estructuras p-n mediante el uso de una fuente solida SOD (spin on dopant por su siglas en ingles) y un proceso termico rapido de difusión (RTP rapid thermal process por sus siglas en ingles), en base al conocimiento previo de la formacion de uniones poco profundas (menores a 0.46m) y de baja resistividad mediante el empleo de esta tecnica. Las mejores caracteristicas de las estructuras fabricadas con esta técnica presentaron valores menores a los calculos teoricos proporcionados por el modelo p-n. Como trabajo futuro se propone una mejora a este proceso.

Publisher

Instituto Nacional de Astrofísica, Óptica y Electrónica

Publish date

2008

Publication type

Master thesis

Publication version

Accepted Version

Format

application/pdf

Language

Spanish

Audience

Students

Researchers

General public

Citation suggestion

Ruiz-Taboada G

Source repository

Repositorio Institucional del INAOE

Downloads

1322

Comments



You need to sign in or sign up to comment.