Temperature effects in Mis solar cells on single crystal p-silicon

Abstract

In recent years the potential use of MIS silicon devices in photovoltaic conversion has been widely demonstrated. MIS solar cells have been studied by many workers [1][2][3][4] as a low-cost alternative to the p -n junction solar cells. MIS solar cell is an improved version of a Schottky barrier solar cell having an ultrathin insulating layer in between the metal and semiconductor which increases the open-circuit voltage. Several recent papers [5][6][7] have described the experimental energy conversion properties of the MIS solar cell, while others [8][9][10] have discussed the theory of this device. However, these papers give very little information about the current conduction mechanism, the role of surface states, nature of the oxide layer and insight about the shunt resistance of the cell. In order to obtain the above information it is necessary to investigate the current-voltage characteristics of an illuminated MIS solar cell over a wide temperature range. However, a few workers [11][12][13][14] have studied the effect of temperature of the performance of MIS solar cells but in most of the work reported, dark I -V curves have been studied to decide whether the device is a minority or majority carrier device. No attempt was made to observe illuminated I -V curves and other diode parameters as a function of temperature.The present letter reports illuminated currentvoltage characteristics of A1-SiO-Si (p-type) solar cells over a wide range of temperature: 100 to 450K. The parameters, like the diode quality factor and series resistance, were also measured in this temperature range. The observed results for the variation of open-circuit voltage (Vow), short circuit current (Isc), fillfactor (FF), efficiency (r/), series resistance (Rs) and diode quality factor (n) with temperature have been discussed and compared with available results.The cells reported here have the structure SiOxAR coating/Ti P d -A g grid/SiO2/Si substrate/A1 back contact. The p-type [1 0 0] 1.0 fl cm silicon wafers were polished on one side and lapped on the other side to form ohmic contact. On the rear side of the wafer an aluminium layer was evaporated and sintered at about 750°C for 5min in argon atmosphere containing traces of oxygen. An oxide layer ~ 3 nm thick was deposited as defined by photolithographic methods and finally the SiOxAR coating (~8 0 n m ) was deposited. The performance parameters for one of the best cells of the batch were measured at room temperature and under A M I ( 1 0 0 m W c m 2) illumination. The following values were found: Voc = 470 mV, I~c = 29.1 mA, FF = 0.66 and active area efficiency (r/a) = 7.0%.The value of diode quality factor (n) was determined from the slope ofln (Isc) against Voc plots at low intensities such that the relation Vo~ -nkT ln (Is~/A) + nc~* nkT ln (A*T 2)q q (2) at a particular temperature. The value of ~b* for our cell was found to be 0.835 eV at room temperature.In order to measure the temperature variation of various parameters, the solar cell was mounted in a specially designed sam...

Vegetation and Soil Carbon Pools of Mixed Plantation of Acacia nilotica and Dalbergia sissoo under Social Forestry Scheme in Kurukshetra, India

“…Further, plantation forests are important sources of commercial forest products that alleviate the pressure on native forests and are viewed as an effective means of short-term carbon sequestration [23]. In India, the potential of short rotation forestry in sequestering carbon has been reported for poplar [5,24,25], eucalyptus, sal, teak [26,27], leucaena, albizzia and acacia [28] species with annual rates of accumulation of carbon ranging from 1 Mg C/ha/yr in sal to 11.8 Mg C/ha/yr in poplar in the Indo Gangetic regions under irrigated conditions. Tree based systems accumulate large amount of biomass and sequester substantial amount of carbon in perennial tree components.…”

“…The above ground and below ground carbon pool as a fraction of biomass was calculated as 32. Government Lands, Institutional Lands, Panchayat Lands, Common Lands and other waste lands to increase the forest and tree cover [5]. The recorded forest area of the state of Haryana is only 3.59% of its total geographical area out of which reserved forests constitute 15.97%, protected forest 74.28% and 9.75% is covered by unclassed forests [6].…”