Coulomb Blockade Voltage Calculator
Compute the Coulomb-blockade voltage e over twice the total capacitance of an island. Formula: Vb [mV] = 80.108832 / C [fF] (since e/(2·C) with e=1.602176634e-19 C, 1 fF=1e-15 F, converted to mV). Input: C > 0 fF. Output: Vb > 0 mV. Assumes an isolated metallic island at zero temperature and that C is the total capacitance to all surroundings.
Description
Calculate the e/(2CΣ) Coulomb-blockade voltage scale from an island's total capacitance.
Compute the Coulomb-blockade voltage e over twice the total capacitance of an island. Formula: Vb [mV] = 80.108832 / C [fF] (since e/(2·C) with e=1.602176634e-19 C, 1 fF=1e-15 F, converted to mV). Input: C > 0 fF. Output: Vb > 0 mV. Assumes an isolated metallic island at zero temperature and that C is the total capacitance to all surroundings.
When to use Coulomb Blockade Voltage Calculator
- Calculate the e/(2CΣ) Coulomb-blockade voltage scale from an island's total capacitance.
- Compare fabrication or device scenarios while holding coefficients and unit conventions constant.
- Check a hand calculation before moving to a higher-fidelity process, circuit, or TCAD model.
How the calculation works
CΣ must include every capacitive coupling to the island; using only one junction capacitance overestimates the voltage scale.
Vb = e/(2CΣ) = 80.1088317/C[fF] mV Interpreting the result
CΣ must include every capacitive coupling to the island; using only one junction capacitance overestimates the voltage scale.
Assumptions and limitations
- The e/(2CΣ) convention is a charging-energy voltage scale; observed thresholds depend on junction asymmetry, offset charge, temperature, and circuit topology.
- Use parameters measured for the same material, geometry, temperature, and operating regime whenever the result informs engineering work.