Development of Heterojunction Diode-Type Gamma Ray Detectors Based on Epitaxially Grown Thick CdTe on -Si Substrates

Room temperature nuclear radiation detectors with energy discrimination capability developed by growing thick cadmium telluride (CdTe) epitaxial layers directly on n⁺-Si substrates in a metal-organic vapor phase epitaxy system is reported for the first time. The CdTe/n⁺-Si heterojunction diode detector exhibited good rectification and charge collection properties. The reverse leakage currents were typically 1times10^-7 to 5times10^-7 A/cm² at 50-V bias. The detector clearly demonstrated its energy discrimination capability by resolving gamma peak from the ²⁴¹Am radioisotope during radiation detection test at room temperature