In wider-gap semiconductors where bipolar conduction is negligible, the twoband model naturally reduces to a single-band model; therefore, materials with R = n / p > 1 are expected to exhibit better n-type TE performance than p-type, while materials with 1/R > 1 are expected to exhibit higher p-type TE performance. Accordingly, for wider-gap semiconductors, the R parameter simply indicates the ratio of the nto p-type TE performance.