Cecile2ndDippingAt4K

2nd dipping at 4K in the Heliox

Resonance at Room Temperature

Remark : I ran the calibration with the averaging on, and the IF Bandwith (10kHz). As a result, we have much less noise.

2T Measurements

Use of the sensitive power supply : 100 micro Volts, 10 nA

4-6 : 5,5 nA

4-12 : 9,5 nA

4-13 : 9,8 nA

4-18 : 9,9 nA

4-16 : 0,4 nA

Remarks : Pin 16 broken, again!

4T Measurements

Use of the AC Lock-in Amplifier : 10 nA (1V through a 100MOhm transformer), 17 Hz of current excitation in Pin 4

13 - 16 : 41 (In) -2 (Out)

12 - 8 : 34 (In) -2 (Out)

12 - 13 : 0 (In) 0 (Out)

8 - 16 : 77 (In) -2 (Out)

All results in micro Volts.

I/Vg - Characterisitc

Use of 2 Lock-in amplifiers synchronized : 500 micro Volts (voltage attenuator) 17 Hz excitation

-> Problem : we can't get a complete depletion (I=0V) of the device. Gate voltages used too high regarding to previous data.

Transfer function

Same parameters than for the IV characteristic

The value of the resonant frequency is 350MH.

TransferFunction.txt

-> Problem: the measures doesn't seem rational, fluctuations in the resonance depth.

Explanation?

After ungrounded all the pins, new experiments

I/Vg - Characterisitc(2)

Procedure :

20 min at Vg=0V, then Vg Up

20 min at Vg=0.4V, then Vg down

If we consider that the 4T resistance can be calculated as V4T/I2T (no current leakage to the ground or through the probes), then we can easily get this graph :

The two last points (400 mV) are unrealistic.

If we compare this graph to Ben's work, we found it very similar, except for Vg up, where I apparently lack some data, and one point is probably false (0,350 mV).

Here is what I get :

RF Data (2)

After waiting 20 minutes at Vg=0.4V

At the end of the experiment at Vg=0V

PCB Board

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