Messages

1

General Questions and Answers / Can ATK simulate AC response of graphene devices?

« on: March 6, 2017, 03:53 »

Hi everyone, I would like to know whether there is a frequency parameter setting in ATK? I modeled a graphene diode, and all results such as I-V curve were achieved under DC case which is the default case.  Now I would like to do the same simulations under AC situation. But I cannot find any frequency-related setting. Could you please give me some hints? Thank you.

2

General Questions and Answers / Re: parameter settings about GNR on hexagonal boron nitride floating gate devices

« on: February 24, 2016, 09:22 »

Hi Jess

Thank you for your reply.

No problem for the 1st question, but for the 2rd one, I would like to get the most stable system and then calculate its IV curve. I ran optimization for GNR on hBN devices before, with DFT, which costed me almost three weeks and offered similar IV curves compared to the non-optimized one. This time I have added a gate in, but based on previous experience, I am hesitating on optimization with DFT which is really time-consuming, even though accurate. That is why I am wondering if I can skip the optimization step or run optimization with Extended Huckel. And I also prefer Extended Huckel for IV curve calculation. Now I am trying to find relevant publications to support my idea.

3

General Questions and Answers / parameter settings about GNR on hexagonal boron nitride floating gate devices

« on: February 24, 2016, 02:58 »

Dear QuantumWise Staff,

I am trying to simulate a GNR on hexagonal boron nitride floating gate device, but have several confusions about configuration, optimization and IV curve calculation settings. Would you please offer me some suggestions or relevant quantumwise tutorial links?

1.  configuration.  The simulation structure is set as follows. I have set the distance between GNR and hBN 3.3A as publications mentioned, but have no idea what value should be set for the distance between hBN and the gate. Personally, I would like to make them contact, which means the distance will be zero or 0.5A. But is it recommended? Or is there any publication has offered theory to guide us choose the value?


2.   optimization and IV curve calculation. DFT is the most reliable method but takes extremely long time. I have tried Extended Huckel for both optimization and IV calculation for GNR floating gate devices and got good results. But I am not sure if Extended Huckel is suitable for devices which contain boron and nitride atoms. It will be great if quantumwise tutorials can be posted for it.

Thank you for help!