Abstract
The effect of bias voltage on the measurement of the local barrier height (LBH) with the STM technique was examined by numerical calculations based on Simmons' formula. Under the condition of constant tunneling current, the effect of bias voltage on LBH reflects the tip-specimen distance. The way of the effect depends on the value of bias voltage. The range of bias voltage can be divided into two. The experimental way to find each range is given. For the bias voltage close to zero, the tip-specimen distance is proportional to a natural logarithm of bias voltage, and LBH value variation with bias voltage is converted to its distance variation. For higher bias voltage, apparent LBH value is lower by the half of the bias voltage.
