I can't help but notice there's no sequence to the videos labeled "19C, 20A, 18B", I'd like to know if there are other videos on the topics and if the rest going to be uploaded? Also, if possible, I would really appreciate more content on HEMT transistors and new material systems such as ScAlN.
I have a question please, in slide 12, examples part b and c, why the Piezoelectic polarization in these directions when tensile and compressivley strained?
@mimi-moosh1026, good question. This is because of the crystal structure. When you stress it laterally, the charge centers (positive and negative charges) will displace differently vertically and form a dipole. This is just like you when you squeeze a ballon horizontally, the ballon will elongate vertically. This is a Wurtzite crystal that has this type of property.
@quantum_computing Thank you very much for the reply and the answer to my question! for the video! It was very educational, informative, and helpful with clear explanations. You're a remarkably perspicuous instructor! If I may ask another question, please, why, when changing to N-face, then the direction of the piezoelectric polarization changes under the same type of stress? if we to apply the concept from your answer shouldn't the direction remain the same? Or we're following the spontaneous polarization convention?
@@mimi-moosh1026 The charge centers of negative and positive charge move in opposite directions under stress. If it is N-face (equivalent make the crystal upsidedown from Ga-face), then you will swap the positive and negative centers and thus the polarization direction changes. Please let me know if it is not clear. Thanks!
I can't help but notice there's no sequence to the videos labeled "19C, 20A, 18B", I'd like to know if there are other videos on the topics and if the rest going to be uploaded?
Also, if possible, I would really appreciate more content on HEMT transistors and new material systems such as ScAlN.
The videos have all been uploaded. The sequence is shown here: ruclips.net/p/PLnK6MrIqGXsIo4AN22EuWJKuv-5OtBpoW
I have a question please, in slide 12, examples part b and c, why the Piezoelectic polarization in these directions when tensile and compressivley strained?
@mimi-moosh1026, good question. This is because of the crystal structure. When you stress it laterally, the charge centers (positive and negative charges) will displace differently vertically and form a dipole. This is just like you when you squeeze a ballon horizontally, the ballon will elongate vertically. This is a Wurtzite crystal that has this type of property.
@quantum_computing
Thank you very much for the reply and the answer to my question! for the video! It was very educational, informative, and helpful with clear explanations. You're a remarkably perspicuous instructor!
If I may ask another question, please, why, when changing to N-face, then the direction of the piezoelectric polarization changes under the same type of stress? if we to apply the concept from your answer shouldn't the direction remain the same? Or we're following the spontaneous polarization convention?
@@mimi-moosh1026 The charge centers of negative and positive charge move in opposite directions under stress. If it is N-face (equivalent make the crystal upsidedown from Ga-face), then you will swap the positive and negative centers and thus the polarization direction changes. Please let me know if it is not clear. Thanks!