ELECTRICAL MODELLING AND OPTIMISATION OF HETEROJUNCTION SILICON SOLAR CELLS

BALENT, JOŠT (author), Krč, Janez (mentor)

In this PhD thesis, we use numerical modelling to study and optimise the structures and performance of silicon heterojunction (SHJ) solar cells. We have established an advanced numerical model of the SHJ cell that includes a description of the defect states in the amorphous layers, takes into account the conducting oxide contact layers as a bulk semiconductor, and correctly describes the transport of free carriers through the heterojunctions taking into account different modes of tunneling transport. The model is stable over a wide temperature range of cell operation (-20 °C to 80 °C). In this thesis, the influence of defect states in highly doped amorphous layers and at the heterojunctions between amorphous and crystalline silicon on the SHJ cell efficiency has been analysed using simulations. Recommendations on the optimisation of the electron affinity of the ITO contact layers were made and the impact on the cell efficiency of varying the electron affinity in the ITO contact layers for different densities of defect states in the highly doped amorphous layers was explained. We have also performed a temperature analysis and provided recommendations for optimising SHJ cells operating at different temperatures in various climatic regions. The results of this thesis contribute to a better understanding of SHJ cell performance and provide guidelines for further development.

• Language: English
• Keywords: Silicon heterojunction solar cells, numerical modelling, electrical simulations, defect states, tunnelling
• Work type: Doctoral dissertation
• Organization: FE - Faculty of Electrical Engineering
• Year: 2022
• PID: 20.500.12556/RUL-140268
• COBISS.SI-ID: 121255939
• Publication date in RUL: 14.09.2022

Secondary language

• Language: Slovenian
• Title: ELEKTRIČNO MODELIRANJE IN OPTIMIZACIJA HETEROSPOJNIH SILICIJEVIH SONČNIH CELIC

Abstract

V doktorski disertaciji z uporabo numeričnega modeliranja proučujemo in optimiziramo strukture in delovanje silicijevih heterospojnih (SHJ) sončnih celic. Vzpostavili smo napreden numerični model SHJ celice, ki vsebuje opis defektnih stanj v amorfnih plasteh, upošteva kontaktne sloje iz prevodnega oksida kot volumski polprevodnik ter pravilno opiše prehajanje prostih nosilcev preko heterospojev upoštevajoč različne načine tunelskega transporta. Model je stabilen znotraj širokega temperaturnega območja delovanja celice (-20 °C do 80 °C). V disertaciji smo z uporabo simulacij analizirali vpliv defektnih stanj v visoko dopiranih amorfnih plasteh ter na spojh med amorfnim in monokristalnim silicijem na izkoristek SHJ celice. Podali smo priporočila glede optimizacije elektronske afinitete kontaktnih slojev ITO ter razložili vpliv spreminjanja elektronske afinitete v ITO kontaktnih slojih pri različni gostoti defektnih stanj v visoko dopiranih amorfnih plasteh na izkoristek celice. Opravili smo tudi temperaturno analizo in podali priporočila za optimizacijo SHJ celic, ki delujejo pri različnih temperaturah v različnih podnebnih območjih. Rezultati disertacije pripomorejo k boljšemu razumevanju delovanja SHJ celice in podajajo smernice za nadaljnji razvoj.

• Keywords: Silicijeve heterospojne sončne celice, numerično modeliranje, električne simulacije, defektna stanja, tuneliranje