 So, I think Professor Solanki explained everything about this bulk creep combination, we are till the diffusion. So, I hope you can put the diffusion values here, like what is put with a peak doping concentration. And suppose you want 300 nanometer junction and the sheet resistance of around say 70 or 50 ohms per square. So, you can check these values to get I mean you can modify these values to get that kind of sheet resistance and junction depth. The other way around is that you know the peak depth peak doping concentration and you want to achieve a certain junction depth, then you can put these values to get to see what is the sheet resistance with this those values. So, you can play with these two parameters to find out what would be the sheet resistance and junction depth of the after the diffusion. And the diffusion type is n type since this is the front diffusion first front diffusion we are saying and the diffusion profile you can select from here. So, uniform for kind of plasma and implantation and Gaussian and Aaron function for the thermal diffusion. And as Professor Solanki mentioned we can also define the back surface field by going to the rear diffusion. So, here you can enable in and put in the same way only thing is that you will achieve some higher value of the junction depth. So, here it is mentioning around 2.75 micrometer. So, you can adjust these values again to get that kind of back surface field. Only thing is that here you have to put the thing as a p type because it is p plus back surface field. So, it is at the back side. So, we will put the p type thing. So, right now I am removing this part. Now, the bulk recombination if you double click on it you will get the tau value at the bulk. That means, the lifetime you can specify in terms of microsecond you will find the net LLI tau you can specify just these values like 100 microseconds and you can see what is the diffusion length as well as the diffusion length. And this LLI means low level injection because this lifetime is also dependent on the injection level. So, at low level injection this is the value. So, you can specify the front surface recombination velocity again at low level injection you can put say let us say 1000. This is the surface recombination velocity to specify at the front surface how much recombination is happening. And you can see the saturation current density here. Similarly, you can put the rear surface velocity. So, again let us put it 1000 this is just some number I am taking. So, by these three combination you can put the material quality and the surface quality. So, first is bulk recombination that is mentioned in terms of the lifetime of the carrier. Second is the front surface recombination velocity that is in terms of the SRV and the back surface recombination velocity. Now, after selecting all these device parameters now comes the point where we put the excitation thing. So, what kind of excitation we are giving? We are giving the one sun AM 1.5 global. So, the solar spectrum is called the AM 1.5 global spectrum. So, that radiation is falling on the surface of the solar cell. So, to select that first you will not find this thing here. So, you go to the excitation on the top menu. So, here you will find option open. If you click open you will find two kind of excitation given. One is one sun excitation the other one is the scan queue. So, the one sun excitation is used for the normal IV measurement of the IV characteristics. How the cell is operating in practice under the sun and the scan queue is for the measuring the quantum efficiency of the cell. See the basic difference between these two is that it is a basically a white light composing of all the wavelengths of different intensity. So, it has a certain spectrum and this scan queue is a excitation file that contains all the wavelengths, but they are irradiated over the cell separately. So, when I select one sun it will give all the wavelength together and the scan queue will give all the wavelengths separately. So, for primary reason I am selecting one sun for to study the IV characteristics. So, if I open it will automatically select all these things. So, here you can see the spectrum is also selected as 1.5 g dot s p c c. If you double click on it you will find as file selected from the external find. So, if you select the excitation from one sun dot e x c it will automatically select all these things. So, you do not need to mention separately, but here you can see other kind of excitation to m 0 for extradiation application m 1.5 d only direct radiation for concentrated kind of solar cell and m 1.5 g. So, excitation file is selected now the whole thing is set now you can just run the thing and see the effect. So, if you just go for run it will display the results at the bottom. What is the open circuit voltage it is around 624 625 millivolts what is the short circuit current it is 3.248 ampere and what will be the peak power. So, from these three values you can calculate a field factor as well as efficiency. Now, let us look at the graphs if you go the graphs you will show some primary graphs out here. So, the first one is sorry this one is the IV characteristics of the solar cell in the negative direction the current is in this direction in the negative direction. The red one is the IV one and the green one is the power versus voltage. You can just select some portion of the cell to see what is happening exactly out there like how exactly I mean for the greater thing. Other than these IV characteristics you can go for different options like energy bands and generation and recombination distance like that. So, all these things are available in the graph section and you will have in special section all the things like what is the doping density this is the for the p type solar cell I mean p type substrate. If you want to see the junction profile. So, if you select the doping density it is just showing the green one. So, that is the base doping density, but actually there is another red one on the side line here. If you just focus here you will find another doping concentration thing happening here can you find it. So, this is the portion. So, this is the profile of the n type thing the carrier n type dopant atoms and this is the for the p type dopant atoms. So, this is the junction. So, you can see what is the junction depth it is around 320 or something like that and the concentration as we said the concentration we have already defined as 1 e to the power 20 peak concentration at the surface. So, this is the diffusion profile and other than that you can also see other things like carrier density is electrostatic potential all these things you can see. Now, if you go for temporal thing it will find that quantum efficiency at the lowest part, but it is not showing here not able it is desirable because we have selected once an excitation. So, it is not showing if you want to measure if you want to see the quantum efficiency let us go back to the parameter menu. So, you click on this you will get back to the parameter thing you just select scan q as the excitation file. Now, again run the simulation and now go back to the thing you will find the e q e and i q e and the reflectance. So, this is the e q e this is i q e and this is the reflectance. So, first you go back to this thing parameter page select excitation file as scan q e scan q e and just the run the simulation once again. Now go back to this graph thing and you will find the i q e e q e and wavelength a reflectance against wavelength. I think in the simulator they are just subtracting this i q e from the 100 percent level. So, this is just the subtraction if you want to save the data of this graph just right click on it sorry not right click go to graph go to particular graph go to this graph you will get the copy graph data. See there are four of two defined graph option one is four curve and the other one is single. So, there are four graphs here if you click on particular graph it will show and then you go to this graph option you will find copy graph data you copy it go to notepad file or something else let us say notepad and just paste it will get all the data out here. You go to a particular graph go to this graph option at the menu you will see the copy graph data you copy it and open a notepad file and just paste it there no three are there the first one is source wavelength this one next is the internal quantum efficiency next is external quantum efficiency and the last one is primary. So, if you want to add let me say suppose you have only two graphs and you want to add one more thing just click on this axis you will get the user defined graph thing. So, here you have the x axis as primary source wavelength or lambda then curve one is internal IQV curve two is external IQV sorry EQV and curve three is primary surface reflectance. So, if you do not have the third thing you just you can just select the what is the thing you can also select the log scale semi log scale all these things from here. Basically, in case of you do not understand which curve is giving you. So, you can just go here and remove other two things you go to none you can understand what is the thing legends I do not think it is given here. So, you can draw separately defined kind of graph. So, if you go here you will find defined you can define anything on this curve thing you know the curve might shift on top of another here reflectance is at bottom. So, it is giving in the bottom yeah you can just put on this leg here and we will see the it will show what kind of curve it is it is. So, you can draw separately defined kind of graph. So, if you go here you will find defined you can define anything on this curve thing you know the curve might shift on top of it it is bottom it will show what curve it is and it will also show the value actually what is the data point everybody is fine with the graph thing graph thing is fine. So, the last thing is the batch to make a batch simulation. So, if you go back here is an option for quick batch or batch if you click it it will open a window like this. So, here you can vary different parameters and give the range and you can see you can put the how many number of steps you want to put in this range and you can see what the output the change in the output due to the change of this parameter. So, first let us assume let us change the background doping from say let us say 1 e to the power 15 to 1 e to the power 17 or 18 and let us say number of steps to be 20. So, we will change the background doping from 15 to 18 and we will see the effect on the output thing like what are the output things like base VOC here base VOC means the open circuit voltage only. So, base means here it is not basic kind of thing it is the VOC of the cell. So, all the things are written here is in terms of base VOC base ISC or base PMAX like that. So, this is as the VOC thing the next thing is the base ISC and base PMAX. So, we will change the background doping in this range and we will see the effect on the these three parameters. Now, if you click ok and run it it will run, but it will not show the results actually you have to click in this contact. So, it is a common mistake. So, sometime it does not show. So, you just select quick batch and you will see all the things I mean listed out here the background doping we have selected from 1 e to the power 15 to 1 e to the power 18 in 20 steps. So, there are 20 steps in which it is it has been selected. So, there are sometime problem in this log scale actually sometimes it jumps from in the initial values and in that it splits the other range in some anyway. So, now if you run it you will see the all the values taking place. So, similarly you can put other things too. So, you can go for multiple options and permute them all these options. So, range varying from these two value to these other base resistivity values varying from other thing and you can get all these details I mean the effect of this variation out here. Now, if you have got these results and you want to copy it. So, if you just go to again the graph section will again copy get the thing like copy batch data. So, you will you can just copy from here and put it in notepad file. So, all the things will be again you can save in notepad file. I think this is the basic thing for PC 1D simulation. Now, again if you want to go back to the excitation kind of thing. So, I think we had selected QE thing. So, that is why it had given some bad results I think actually it was set as scan QE that is why it was giving some bad results. So, this is the actual results for once an excitation. So, that is all I hope and one last thing is that if you are not able to put any kind of values you can just open a default file for a silicon solar cell like PV cell and it will it will give the very basic cells saved in the PC 1D software. So, it will give the all the values ready made for you. So, you can see for as made for reference you just go to file option open and you will find all different type of devices loaded here. Yeah, this is bipolar junction transistor and out. So, you can all you can simulate all these things here out here. So, different type of device you can simulate out here. So, for that you have some kind of reference device. So, questions? So, one more can be made is here to help you. So, now you can actually go around and have a look. So, Karthik, James, Nehul and so on is here. So, please when you are in the test take all the popular parameters rather I mean rather not use to the best way. So, what do you think? What do you think is the electrical equivalent circuit of the solar cell? So, what was the equation of solar cell? This is equation of solar cell. What does this represent? This represents diode and this is light generated current, it is a current source. So, you need to have a current source, the current this current the current from the current source is in the opposite direction of the diode. So, diode has to be in the opposite direction. So, diode has to be like this with of course, then you can you need to you can put series resistance and shunt resistance and the here is your voltage. This is light it is light dependent current. So, depends on the light. What is the? I do not think there is any symbol. You can create one. That is I think with photodour or something. How to measure RSH? In RSH you can do it looking at the IV curve of solar cell. From the IV curve and there are various methods by for measuring series and shunt resistance of a solar cell. So, measuring typical value for RSH is in it should be in milli ohms 1 to 5 milli ohms it should be small RSH should really be small and RSH the shunt resistance should really be large. So, it will be 500 ohms kilo ohms that range. So, a shunt resistance should be very large ideal infinity series resistance should be very low ideally 0. If you connect many cells in series RSH should be added. It is just like you are adding if one series resistance of cell is 1 milli ohm. If you are putting 10 in series it will become 10 milli ohm of the combination. So, I do not think the lecture on the modules is being planned in this 5 days, but in the when we discuss the module we discuss what is the IV curve of the module in which we add series resistance, divide the shunt resistance, add the current voltage whatever depending on the series and parallel combination of cells. So, similar to this you can also write the IV characteristic of a module. Of course, this the equation that you see on the top does not take care of the series resistance and shunt resistance, but you can also add within that series and shunt resistance and you can have the modified IV equation of a solar cell. Just listen one minute just do on one assignment without that you will not get T today on your computer make a solar cell which is exactly 10 percent efficient not 9.5 not 10.5 10 percent efficient and show me the IV curve of the 10 percent efficient solar cell exactly 10 not 9.5 not 10.5. So, what does it mean you need to adjust the parameters such that you get a 10 percent efficient solar cell. So, do not write directly cell efficiency equal to 10 percent except that you can adjust any parameter that you want. Do it and as soon as you make a 10 percent efficient solar cell you can leave for the T. One more thing so the simulator will not give you the efficiency directly. So, what you have to do is it gives a P max value it gives a P max value which is V m times I m then you can actually and it also gives V o c and I s c. So, you can calculate the fill factor you can you know the V o c I s c and then from the last expression you can actually calculate the efficiency. So, you do this it gives this. So, you know this you know V o c I s c you know this from here. So, you can calculate the fill factor once you know the fill factor this is the expression for the efficiency V o c I s c fill factor divided by P in. What is P in you have to take 1000 watt per meter square. So, make sure that you are using your cell area also appropriately 1000 watt per meter square and convert meter square into centimeter square otherwise your efficiency will be some 1000 or something V m voltage at the maximum power point. So, this just draw the V m and I m. So, the V m is the voltage at the maximum power point and I m is the current at the maximum power point and from the V i curve which also show the I s c and V o c. So, from the V i curve you know I s c and V o c value and at the maximum power point current at the maximum power point is I m voltage at the maximum power point is V m. So, now, you need to make a 10 percent efficient solar cell. If you have got the 10 percent please help your neighbor please help your neighbor to get 10 percent. Yeah, British go around and help people 10.33 not acceptable 10 it has to be 10 9.96 is very close. So, you can change any parameters you have to make actually the default file gives what efficiency default file gives. So, the default file gives you 13 percent. So, you actually make the cell worse you know you do whatever you want you reduce the lifetime you reduce you increase the reflectance you increase the surface recombination velocity. So, you can start with the default file which gives you 13 percent efficiency go from 13 percent to 10 percent by changing the parameter by making the worse parameter. If anybody got the 10 percent please help your neighbors 10.4 is not acceptable 10.04 is ok 99.4 9.94 9.94 is ok you still not got the 10 ok where are you what you got yes it is practical you can do that possible I mean you cannot make a 5 micron junction test you can make up to 1 micron yes yes that is why people want to make a thinner than thinner going deeper is very difficult you got it why I mean you cannot make a bed cell normally it is difficult to make a good cell, but I think bed was should be easy what surface recombination velocity. So, least is better right you have to make take the worse yeah. So, you have to take 1 million 10.46 then you will get less than 10 percent immediately you take 1 microsecond or 0.1 microsecond. So, to make the choice worse. So, help others anybody who got it help others otherwise T is getting cold got it how much you are getting yeah you have to be very close to 10 you can change it one simple thing to change is reflectance you will reflect more light exactly 10 percent ok wonderful. So, now you can go for T 10.15 is still large difference people were people make so much effort to just increase by 0.1 percent ok. So, one simple way to reduce the efficiency is to increase the reflectance very simple other simple way to do it increase your decrease your life time base life time. Third simple way is increase your surface recombination velocity is to very high value 11.29 still high 10.7 no it is a big difference 9.96 is ok let us stop now because the next section will get delayed.