App note from ROHM Semiconductors about the cautions when measuring temperature from PN Junctions. Link here (PDF) The forward voltage of a pn junction can be measured to estimate the junction temperature of a semiconductor device. However, correct results may not be obtained if the measurement is performed incorrectly.
Old app note from Maxim Integrated about high-precision temperature measurement. Link here (PDF) Many industrial and medical applications require temperature measurements with accuracies of ±1°C or better, performed with reasonable cost over a wide range of temperatures (-270°C to +1750°C), and often with low power consumption. Properly selected, standardized, modern thermocouples paired with high-resolution ADC […]