Electronics10 mm to 100 nm
25.9meV
Every switch on a chip competes with thermal noise of 25.9 meV.
17.9 meV: kT ln 2, the Landauer limit
The physics of devices: quantum, semiconductors, electronics, photonics.Figures checked
The physics of devices, with the numbers.
Scroll from a chip in your hand to the atom inside it.
Scroll
Semiconductors100 nm to 5 nm
1.12eV
Silicon’s gap is 1.12 eV. Lower the barrier under the gate and current flows.
Photonics5 nm to 0.5 nm
0.80eV
A 1550 nm photon carries 0.80 eV and passes through silicon. Above 1.12 eV it is absorbed: one electron, one hole.
Quantum physics0.5 nm to 10 pm
13.6eV
Freeing the electron of hydrogen takes 13.6 eV. Every level sits at 13.6/n² eV below the edge.
One energy window, four subjects. The quantities these pages compute, on a single scale from the thermal energy of a transistor to the ionisation of hydrogen.
CODATA 2018, materials libraryQuantum physics
21 articlesStart here
Semiconductors
16 articles, 3 calculatorsStart here
Electronics
11 articlesStart here
Photonics
11 articles, 1 calculatorStart here
Instruments
Ten calculators, free, one answer at a time. Every result prints its source and a citation.
Semiconductors 3 live
Energy-loss calculator
Particle, material and thickness in; mean loss, most probable value and straggling out.
Bethe and LandauMaterials librarySearch and compare density, excitation energy and radiation properties for 17 materials.
PDG and NISTDetector signal calculatorElectron-hole pairs and fully collected charge in silicon and germanium.
PDG; NIST ESTARFirst planned: Intrinsic carrier density and band gap against temperatureSi, Ge, GaAs, SiC, GaN
Photonics 1 live
Photon attenuation calculator
Half-value layer and transmission for gamma and X-ray beams through common materials.
NIST XCOMFirst planned: Fibre link budget and attenuationITU-T G.652, G.657
Radiation 6 live
Radioactive decay calculator
Calculate decay and daughter activity.
NNDC NuDat 3Accelerator power and synchrotron loss calculatorCalculate dipole radiation for one beam in an isomagnetic ring.
CODATA 2018; Sands SLAC-121Gamma dose rate calculatorCalculate air kerma from an isotropic point gamma source: K̇ = Γδ A / d², with optional shielding.
NNDC; NIST; LNHBQuantum physics planned
First planned: Photon energy, wavelength and frequency converterCODATA 2018
Electronics planned
First planned: MOSFET long-channel current and thresholdSze, Tsividis
Also in Radiation: Cosmic radiation and flight dose calculator, X-ray tube spectrum and filtration calculator, Radiation units converter. All ten instruments
Start here
The first article of each pillar’s reading path. Each path goes from the first concept to the current state of the field in five or six pieces.
Max Planck’s Impact on the Birth of Quantum PhysicsMax Planck didn't set out to break physics -- his 1900 fix for the blackbody radiation problem introduced the quantum and he spent years doubting it.Charge Carriers in Semiconductors: Electrons, Holes and Pair CreationCharge carriers in semiconductors are electrons and holes. See how a 1.12 eV band gap in silicon creates them and why a particle needs about 3.6 eV per pair.How does a CCD sensor work? A pixel’s charge can travel 4,096 steps before it is readYour phone reads each pixel where it sits. A CCD passes every pixel's charge, step by step, to an amplifier at the edge of the chip.Are Photons Matter? The Answer Has an Error BarAre photons matter? No — but "massless" is a measured bound, not an assumption, and the number keeps moving by orders of magnitude.
Latest
Across the four pillars, newest first.
ElectronicsHow does a CCD sensor work? A pixel’s charge can travel 4,096 steps before it is readYour phone reads each pixel where it sits. A CCD passes every pixel's charge, step by step, to an amplifier at the edge of the chip.ElectronicsAn H100 operation costs about 100 million Landauer limitsPhysics sets a floor for erasing one bit. At peak, an H100 spends about 100 million times that energy per operation: a scale, not a like-for-like test.PhotonicsWhy data in optical fibre is 32% slower than lightData in fibre is often said to move at the speed of light. In standard fibre it moves at 204,107 km/s, 68.1% of it, because the glass slows the pulse.ElectronicsCosmic Rays and Silent Data Corruption in Data CentresCosmic-ray neutrons are real, but field studies point to hardware defects behind most DRAM faults and the silent core errors operators have traced.SemiconductorsMoS2 Radio Survives Nine Months in Orbit: What It ShowsA 2026 orbital MoS2 radio experiment ran for nine months. Its measured error rate supports a promising result, with mission qualification still ahead.Quantum physicsQuantum Error Correction Threshold Theorem: Why Scale HelpsQuantum error correction threshold theorem: why Google's Willow gets more reliable as it scales, while near-threshold chips don't.ElectronicsIntel Glass Core Substrate: Why It’s Not ShippingIntel's glass core substrate is not in Clearwater Forest, which uses organic substrate and EMIB. What ECTC 2026 showed, and why glass is years away.Quantum physicsOne-Dimensional Anyons: Breaking Statistics Without BraidingOne-dimensional anyons ditch braiding entirely — cold-atom experiments show head-on collisions alone tune quantum statistics continuously.Quantum physicsMagnon Qubit Quantum Computing: Wrong Job Title?Magnon qubit quantum computing headlines miss the point: real experiments show magnons acting as quantum memory, not stand-alone qubits.Electronics3D Chip Stacking’s Thermal Limit Splits Cache From Cores3D chip stacking's thermal limit lets cache stack almost free, but logic-on-logic still cooks itself — a split that won't close for years.ElectronicsData Center SSD Shortage 2026: Why NAND Lost to DRAMThe 2026 NAND and SSD shortage comes from fabs moving lines to DRAM and HBM. NAND contract prices rise 15 to 20% in 4Q26; plan for tight supply into 2027.PhotonicsSiPM vs PMT: Why Silicon Hasn’t Won Everywhere YetSiPM vs PMT: silicon wins on efficiency, voltage and magnetic immunity, but tubes still win on collecting area per euro. The numbers and a verdict.